Methods for cleaning filtration system media

ABSTRACT

The present disclosure provides improved methods for conducting a wash cycle in a filtration unit. The methods may be used alone or in combination with one another to achieve the improvements described herein. Filtration units adapted for carrying out the novel methods are also provided. Through the use of the methods and filtration units described, significant economic benefits are obtained without a significant increase in the costs of the filtration unit or in the costs of operation of the filtration unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure claims the benefit of and priority to theearlier-filed PCT Application No. PCT/US2017/023258, filed on Mar. 20,2017, published as WO2017/161381 on Sep. 21, 2017, and U.S. provisionalapplication (62/310,376) filed on Mar. 18, 2016, the entire contents ofwhich are hereby incorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to improved methods forcleaning filtration media. More particularly, the present disclosurerelates to improved methods for cleaning filtration media used infiltration systems, including filtration systems used in connection withthe treatment of wastewater for reduction of suspended solids.

BACKGROUND OF THE DISCLOSURE

Disposal and reuse of wastewater is problematic. Stringent wastewatertreatment requirements have been promulgated to protect human health,particularly in those areas having limited water supply or densepopulations. For example, Title 22 of the California Administrative Codeestablishes stringent water reuse criteria where human contact is likelyto occur with treated wastewater.

For a variety of reasons, porous filtration media is commonly used influid treatment. However, the use of granular filtration is not withoutdrawbacks and can be the limiting factor from a filtration capacitystandpoint for a fluid treatment system. Porous filtration mediaincludes porous solids, such as sand, gravel and anthracite coal, aswell as synthetic porous filtration media.

Synthetic porous filtration media are increasingly being used inwastewater filtration applications. One type of synthetic porousfiltration media that has been used by the applicants of the presentdisclosure is described in U.S. Pat. No. 7,374,676. Such media comprisesa plurality of crimped fibrous lumps that are capable of beingcompressed in order to adjust the porosity and the size of the particlesthat are trapped or captured by the fibrous lumps. Such media arereferred to herein as “compressible filtration media.” In operation of afiltration system comprising the compressible filtration media, thecompressible filtration media is compressed to define a porositygradient in the filter media bed proceeding progressively from moreporous to less porous in the direction of the flow of the influent fluidso that filtration proceeds in a direction from a more porous to a lessporous filter media bed and passing an influent fluid containingparticles through the filter media bed. In such operation, the largerparticles are initially retained or captured in the portion of thefilter media bed where the compressible filtration media have thelargest pore size and smaller particles are retained or captured laterin the portion of the filter media bed where the compressible mediafilter has smaller pore size.

Regardless of the type of porous filtration media used, the filtrationmedia is required to be cleaned periodically to remove captured solids.This cleaning process is referred to as backwashing, which entails usinga washing fluid to agitate the filtration media and allow for theaccumulated solids to be removed. In such backwashing operations it isimportant to minimize the amount of washing fluid in the process as suchwashing fluid will have to be subject to treatment or otherwise disposedof and to minimize the amount of time spend during the backwashingprocess in order to maximize the efficiency of the filtration unit.Furthermore, it is desirable to eliminate or minimize the use ofchemical cleaning agents during the backwashing process due to theexpense of the chemicals and the potential need for separate disposal ofthe washing fluid exposed to the chemical cleaning agents. Finally, itis desirable to remove as much of the accumulated solids from thefiltration media as possible during the backwashing operation in orderto minimize the time in between subsequent backwashing operations. Inoperation, the frequency and duration of backwashing operations maydepend on the type of porous filtration media used, the solids contentand particle size distribution of the fluid being treated and operationparameters of the filtration system (for example, the flow rate of thefluid being subject to filtration).

While methods exist to clean porous filtration media, the art is in needof improved methods for cleaning porous filtration media that result inat least one of the following: i) minimizing the amount of washing fluidused in the cleaning process; ii) reduce the amount of time required forthe cleaning process; iii) provide increased time between each washcycle while maintaining fluid filtration above a minimum acceptablelevel; iv) eliminating the requirement for chemical cleaning agents tobe used during the cleaning process; v) to increase the life of thefiltration media; and vi) to maximize removal of the captured particlesfrom the filtration media during each wash cycle. Such needs areespecially applicable to synthetic porous filtration media such ascompressible media filters.

The present disclosure provides a solution to the problems of cleaningporous filtration media, particularly synthetic porous filtration media,such as compressible filtration media, by providing improved methods forcleaning porous filtration media and filtration units comprisingcomponents designed to carry out such methods.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a schematic of a prior art device for fluid filtrationusing compressible filtration media during the filtration process.

FIG. 2A shows a schematic of a prior art device for fluid filtrationusing compressible filtration media during the washing process.

FIG. 2B shows a detailed view of the structure involved in the washingprocess using the prior art device.

FIG. 3A shows a schematic of an improved filtration device incorporatingthe directed scouring fluid method for fluid filtration using porousfiltration media during the washing process.

FIG. 3B shows a detailed view of the improved filtration deviceincorporating the directed scouring fluid method.

FIG. 3C shows a side view of the device of FIG. 3A illustrating thepresence of multiple scouring fluid inlet pipes.

FIG. 3D shows a detailed view of two embodiments of the scouring fluidnozzle.

FIG. 3E shows a detailed view of two additional embodiments of thescouring fluid nozzle.

FIG. 3F shows a detailed view of two additional embodiments of thescouring fluid nozzle.

FIG. 3G shows an example of the formation of a jet force gradient alongthe length of a single scouring fluid inlet pipe (upper panel) or acrossmultiple scouring fluid inlet pipes lower panel).

FIG. 4A shows a schematic of an improved filtration device incorporatingthe transition plenum method for fluid filtration using porousfiltration media during the washing process.

FIG. 4B shows a detailed view of the transition plenum with the locationof the effluent pipe positioned below the upper plate.

FIG. 4C shows a schematic of an improved filtration device incorporatingthe directed scouring fluid method and the transition plenum method forfluid filtration using porous filtration media during the washingprocess.

FIG. 5 shows a full scale commercial size 3 foot by 3 footcross-sectional area filter unit constructed specifically to perform theDegree of Cleaning testing. This specially designed testing filter wasdesigned such that it could be set-up in either the prior artconfiguration (the “Old” Configuration) or the improved configuration asdescribed in the present application (the “New” Configuration).

DETAILED DESCRIPTION

Definitions

As used herein, the term “fluid” refers to a substance that has no fixedshape and yields easily to external pressure, such as a gas or a liquid.

As used herein, the term “scouring fluid” refers to a fluid having theappropriate physical characteristics, such as density and buoyancy,relative to the characteristics of the particle removal fluid (asdefined below), such that when the scouring fluid has a positivebuoyancy in the particle removal fluid and provides a motive forcesufficient to produce agitative motion of filtration media in a filtermedia bed during the wash cycle of a filtration device; in a preferredembodiment, the scouring fluid is a gas, such as, but not limited to,compressed air.

As used herein, the term “particle removal fluid” refers to a fluid thathas the appropriate physical characteristics to serve as thetransportation medium to remove the contaminant particles dislodged orloosened from filtration media during a wash cycle of a filtration unit;in a preferred embodiment, the fluid is a liquid.

As used herein, the term “transition zone” refers to an area that iscreated only during the wash cycle where there is no clearly definedinterface or boundary between the scouring fluid and the particleremoval fluid and which is created, at least in part, by the energy ofthe scouring fluid exiting the bulk particle removal fluid.

As used herein, the term “transition plenum” refers to the area of thetransition zone that is created below the level of the upper place in afiltration unit during a wash cycle.

As used herein, the term “porous filtration media” refers to filtrationmedia that contains pores or capture points that are capable of trappingparticulates contained in a fluid stream within the pores or capturepoints when the fluid stream is passed through a filter media bedcontaining the filtration media.

As used herein, the term “synthetic porous filtration media” refers tofiltration media that is manufactured from synthetic components, such asbut not limited to synthetic fibers, and contains pores or capturepoints that are capable of trapping particulates contained in a fluidstream within the pores or capture points when the fluid stream ispassed through a filter media bed containing the filtration media.

As used herein, the term “compressible filtration media” refers tosynthetic porous filtration media, wherein the filtration media form aporosity gradient in the filter media bed when a compression force isapplied to the filtration media, wherein the porosity gradient is leastporous at the point of application of the compressive force and becomesprogressively more porous as the distance from the compressive forceincreases.

Introduction

The basic goal of filtration, whether for gasses or liquids, is toremove contaminant particles in an influent stream to produce aneffluent stream that contains a reduced number or concentration of thecontaminant particles. The contaminant particles in the influent streamare said to be “captured” when they are trapped by the filtration mediaand removed from the influent stream, producing an effluent stream thathas a reduced number of contaminant particles. Over time, the filtrationmedia as a result of the capture of the contaminant particles in theinfluent stream fails to filter further contaminant particleseffectively and is said to be full. Therefore, the filtration mediarequires periodic cleaning to remove the captured contaminant particlesfrom the filtration media. The type of influent stream, the volumetricflow rate of the influent stream, the amount of contaminant particles inthe influent stream and the size/composition of the contaminantparticles in the influent stream are factors in determining how oftenthe filtration media need to be cleaned. Therefore, when describing thefiltration of fluids, the filtration process can be described as havingtwo basic phases, a filtration cycle to remove contaminant particlesfrom the influent stream to be filtered or treated and a washing cycleto remove the trapped contaminant particles to clean or regenerate thefiltration media.

The important parameters for the filtration cycle are: i) thepercentages of contaminant particles removed from the influent stream;and ii) the particle size of the contaminant particles that can beremoved from the influent stream. The higher the percentage of removalof the contaminant particles and the smaller the size of the contaminantparticles removed from the influent stream, the better the performanceof the filtration unit. The important parameters for the wash cycle are:i) the completeness of the wash in terms of how much of the trappedcontaminant particles are removed; ii) the time required for the washcycle; and iii) the volume of washing fluid, which is referred to hereinas particle removal fluid, required to be used during the wash cycle.The more complete the removal of the captured contaminant particles fromthe filtration media, the better the performance of the wash cycle. Whena higher percentage of the contaminant particles are removed from thefiltration media during the wash cycle, the filtration media functionsmore efficiently and increases the time to the next wash cycle,increasing the efficiency and cost-effectiveness of the filtration unit.Furthermore, the shorter the duration of the wash cycle the better asthe filtration unit is off-line for less periods of time. Any time spentin the wash cycle, reduces the time the filtration unit can be inoperation, which can lead to decreased volumes of influent that can befiltered and/or the need for additional filtration units, each of whichincreases the cost of operation and decreases cost-effectiveness.Finally, the less volume of particle removal fluid used the better asthe particle removal fluid used in the wash cycle will ultimately besubject to subsequent reprocessing, filtration or disposal. In manysystems, the particle removal fluid used in the wash cycle is recycledto the head of the plant and, thus, adds to the volume of influent thatmust be filtered. In other systems, the particle removal fluid used inthe wash cycle requires separate disposal. Therefore, wash cycles thatuse less particle removal fluid increase the cost-effectiveness of thefiltration unit.

The present disclosure provides improved methods of increasing theefficiency of the wash cycle. The methods disclosed may be used with anytype of porous filtration media, particularly synthetic porousfiltration media and more particularly compressible filtration media.The present disclosure also provides improved filtration units adaptedto carry out such methods. The methods and filtration units of thepresent disclosure are exemplified using compressible filtration media,however other types of porous filtration media may be used with themethods and filtration units of the present disclosure.

The present disclosure provides two methods of conducting a wash cyclefor use in a filtration device, such as, but not limited to, afiltration device comprising a filter bed comprising porous filtrationmedia units. Such methods in one embodiment increase the efficiency ofthe wash cycle. The two methods are referred to as a directed scouringfluid method and a transition plenum method. The methods may be usedalone or in combination with one another to achieve the results and/orimprovements described herein. In certain embodiments, the increasedefficiency of the wash cycle results in at least one of the following:i) an improved degree of cleaning of porous filtration media,specifically including compressible filtration media; ii) a higherpercentage of removal of trapped contaminant particles from the porousfiltration media, specifically including compressible filtration media;iii) a decreased wash cycle time; iv) a reduced amount of particleremoval fluid required to be used during a wash cycle; v) an increasedinterval between wash cycles; and iv) an increase in the interval oftime between cleaning with the aid of chemical additive cleaning agents.The foregoing benefits, in certain instances, may be made in comparisonto wash cycles using the methods of the prior art. An exemplaryfiltration unit using a wash cycle of the prior art is disclosed herein.Therefore, the present disclosure provides improved methods forconducting a wash cycle for use in cleaning porous filtration media,particularly including synthetic porous filtration media andcompressible filtration media, as well as improved filtration unitsconfigured to carry out such methods. As a result, significant economicbenefits are obtained without a significant increase in the costs of thefiltration unit or in the costs of operation of the filtration unit.

Description of Prior Art Device

A prior art filtration unit for use in fluid filtration is shown inFIG. 1. The filtration unit comprises a housing 2, a plate actuator 3,an upper moveable plate 5 containing a plurality of perforations 13 a, abottom plate 7 containing a plurality of perforations 13 b, filter mediabed 9 comprising the compressible filtration media, an influent pipe 15,an effluent pipe 17 for the particle removal fluid (PRF), an effluentpipe 16 for the filtered effluent and a scouring fluid inlet pipe 19.The filter media bed 9 contains a plurality of compressible filtrationmedia contained by the housing 2 and the upper 5 and lower 7 plateswhich contain perforations (13 a and 13 b, respectively) to allow thefluid to flow through while still retaining the compressible filtrationmedia in the filter media bed 9. The upper plate 5 is lowered by plateactuator 3 to compress the filter media bed 9. The influent pipe 15introduces an influent fluid 11 (for example water) to be filtered; thefluid contains contaminant particles 21 to be filtered and removed fromthe influent fluid 11. The fluid 11 passes through the filter media bed9 and exits the unit 1 through the effluent pipe 16. The contaminantparticles 21 a are retained or captured by the compressible filtrationmedia in the filter media bed 9. As discussed above, the compressionresults in a porosity gradient in the filter media bed 9 proceedingprogressively from more porous to less porous in the direction of theflow of the influent fluid to be filtered so that filtration proceeds ina direction from a more porous to a less porous filter media bed 9. Insuch operation, the larger particles are initially retained or capturedin the portion of the filter media bed 9 where the compressiblefiltration media have the largest pore size and smaller particles areretained or captured later in the portion of the filter media bed 9where the compressible media filter has smaller pore size. Thefiltration unit 1 operates in this manner until the compressiblefiltration media is in need of cleaning.

FIG. 2A shows the wash cycle in the prior art device of FIG. 1. Inoperation the upper plate 5 is moved upward to provide an expandedfilter media bed 9. When the filter media bed has been expanded, ascouring fluid 23 (SF; for example air) is released under the media bedthrough scouring fluid inlet pipe 19 and a particle removal fluid 30(PRF; for example water) is introduced through influent pipe 15. Thetypical flow rates for the SF 23 range from a low of 10 cubic feet perminute per square foot of media (as measured cross sectional to thedirect of flow) to a high of 20 cubic feet per minute per square foot ofmedia. The typical flow rates for the PRF range from a low of 10 gallonsper min per square foot of media (as measured cross sectional to thedirection of flow) to a high rate of 40 gallons per minute per square ofmedia. In the prior art device, the SF 23 is pressurized air (forexample delivered at around 8 lbs pressure). As the SF 23 rises into thefilter media bed 9 due to buoyancy forces, it passes through theperforations 13 b in the lower plate 7 and induces an agitative motionto the compressible filtration media in the expanded filter media bed 9.This agitative motion, exemplified by the arrows 25, creates collisionsbetween individual compressible filtration media with one another andwith the housing 2 and other components of the unit 1. These collisionscause the captured contaminant particles 21 b to be released from thecompressible filtration media yielding released contaminant particles 21c which are carried by the PRF 30 away from the expanded filter mediabed 9 and exit the unit 1 through effluent pipe 17. In the prior artdevice, the wash cycle lasts for 24 minutes. Following completion of thewash cycle, the system is purged for an additional 6 minutes to push thePRF with the release contaminant particles 21 c completely out of thefiltration unit.

FIG. 2B shows a detailed view of the scouring fluid inlet pipe 19,illustrating the flow of the SF 23 (arrows 26) through the scouringfluid pipe 19 and the release of the SF 23 through exit channels 19 adisposed on the bottom portion of the scouring fluid inlet pipe 19 (theportion of the pipe farthest away from bottom plate 7). As can be seen,the SF 23 is initially directed downwards away from the expanded filtermedia bed 9, dissipating a substantial portion of the motive force ofthe SF 23. As the bottom portion of the unit is filled with the PRF 30,buoyant force causes the SF 23 to rise and to pass through perforations13 b in lower plate 7 to agitate the expanded filter media bed 9 (notshown in FIG. 2B).

However, due to the loss of energy/motive force in the SF 23, theinduced agitation is not sufficient to remove all of the contaminantparticles 21 b captured by the compressible filtration media. As aresult, the compressible filtration media retain a portion of thecontaminant particles 21 b even after completion of the wash cycle. Thisportion increases over time. In the prior art device described, it isestimated that 10 to 30% of the contaminant particles 21 b are retained.As such, over time the compressible filtration media cease to functionefficiently and requires restorative cleaning involving chemicaladditives (such as detergents and the like) or replacement. Either ofthe options above require the filter unit to be off line for an extendedperiod of time decreasing the amount of fluid filtered by the unit andincreasing the costs of operation.

A more efficient wash cycle would alleviate these problems. Therefore, amethod for increasing the efficiency of a wash cycle and filtration unitadapted to implement such methods are needed that achieve at least oneof the following: i) an improved degree of cleaning of porous filtrationmedia, specifically including compressible filtration media; ii) ahigher percentage of removal of trapped contaminant particles from theporous filtration media, specifically including compressible filtrationmedia; iii) a decreased wash cycle time; iv) a reduced amount ofparticle removal fluid required to be used during a wash cycle; v) anincreased interval between wash cycles; and iv) an increase in theinterval of time between cleaning with the aid of chemical additivecleaning agents.

Methods and Filtration Unit for Increasing the Efficiency of a WashCycle

The present disclosure provides for an improved filtration unitincorporating one or both of a directed scouring fluid and/or atransition plenum method. The operation of each is described below.

Directed Scouring Fluid

In a first embodiment, a directed scouring fluid method is described forimproving a wash cycle as well as an improved filtration unitincorporating the direct scouring fluid improvement (FIGS. 3A to 3F).The method is described in conjunction with the features of the improvedfiltration unit for simplicity. This example is not meant to limit theapplication of the directed scouring fluid method to the embodiment ofthe filtration unit incorporating the directed scouring improvementdescribed herein. The method may also be incorporated into otherfiltration units and this description is not intended to be limiting.The scouring fluid inlet pipes as described herein may be usedindependently of the particular filtration device described herein andare a particular improvement that can be used independently of theparticular filtration device described herein. For example, and withoutlimitation, the directed scouring fluid method may be used in filtrationdevices where the upper plate 105 is in a fixed position, where thelower plate 107 is moveable, where both the upper 105 and lower 103plates are fixed or where the filtration unit only comprises an upperplate 105. As used herein the term “plate” when referring to the upperand lower plates means an element capable of containing the porousfiltration media and is not limited to the metal plates describedherein. Furthermore, the presence of the accessory components are notrequired to be present in each embodiment of a filtration unitincorporating the directed scouring fluid method. For example, andwithout limitation, the effluent pipe 16 may be absent in certainembodiments and the effluent pipe 17 may function to remove the PRF andthe influent fluid.

In a most basic embodiment, the filtration unit 100 adapted to carry outthe directed scouring fluid method comprises a scouring fluid inlet pipe119 comprising a plurality of scouring fluid nozzles 150. In aparticular embodiment, the filtration unit 100 adapted to carry out thedirected scouring fluid method comprises in addition to a scouring fluidinlet pipe 119 comprising a plurality of scouring fluid nozzles 150, oneor more of the following: a housing 102, an upper plate 105, a filtermedia bed 109 comprising a plurality of porous filtration media units,at least one influent pipe (such as influent pipe 115, which may serveas the influent pipe for both the influent fluid 111 and the PRF 130)and at least one effluent pipe (such as effluent pipe 117 which mayserve as the effluent pipe for both the influent fluid 111 and the PRF130). Such filtration unit may also further comprise a bottom plate 107,and each of the upper 105 and lower 107 plates may containing aplurality of perforations 113 a and 113 b, respectively. Furthermore,the filtration unit may further comprise additional influent andeffluent pipes, a plate actuator to provide movement of at least one ofthe upper 105 or lower 107 plates relative to one another or to providedifferential movement of the plates relative to each other and otheraccessory components common in filtration units.

In the embodiment shown in FIG. 3A, the improved filtration unit 100comprises a housing 102, a plate actuator 103, an upper moveable plate105 containing a plurality of perforations 113 a, a bottom plate 107containing a plurality of perforations 113 b, filter media bed 109comprising a plurality of porous filtration media units, particularlycompressible filtration media, an influent pipe 115, an effluent pipe117 for the PRF 130, an effluent pipe for the influent fluid, and ascouring fluid inlet pipe 119. The filter media bed 109 is contained bythe housing 102 and the upper 105 and lower 107 plates which containperforations, 113 a and 113 b, respectively, to allow the fluid (forexample PRF 130 and influent fluid) to flow through while stillretaining the porous filtration media in the filter media bed 109. FIG.3A shows the filtration unit in a wash cycle.

The scouring fluid inlet pipe 119 comprises a plurality of scouringfluid nozzles 150 in fluid communication with the SF 123 (see FIGS.3A-3F). The scouring fluid nozzle 150 comprises a restriction point asdescribed herein. The restriction point is a domain within the scouringfluid nozzle having a reduced cross sectional area (for example, areduced diameter) as compared another portion of the scouring fluidnozzle or as compared to opening 151 on scouring fluid inlet pipe 119through which the SF 123 must travel before it exits the end of thescouring fluid nozzle. The restriction point may be located at any pointwithin the scouring fluid nozzle.

The scouring fluid nozzle 150 comprises in one aspect a riser portion152, the riser portion having an open first end 152 a and an open secondend 152 b joined by side walls 152 d and forming a passage 152 c, and arestriction point 153. The SF 123 enters the riser 152 through end 152a, travels through passage 152 c and exits through end 152 b. Thejunction of the riser with the opening 151 is a sealed junction. In thisaspect, the restriction point 153 is a domain within riser 152 having areduced cross sectional area (for example, a reduced diameter) ascompared another portion of the scouring fluid nozzle (for example, ends152 a and/or 152 b) or as compared to opening 151 on scouring fluidinlet pipe 119 through which the SF 123 must travel before it exits theend of the scouring fluid nozzle

Bernoulli's principle requires the velocity of the SF 123 to increase asit passes through the restriction point 153, imparting a jet force(illustrated by arrow 127) to the SF 123 as it travels through passage152 c and/or exits the scouring fluid nozzle. The jet force 127 isprovided while the flow rate of the scouring fluid is constant (forexample, for SF delivered to the scouring fluid inlet pipe 119 at a flowrate of 10 CFM/ft², the velocity of the SF will be increased when usinga scouring fluid nozzle 150 as described as compared to a scouring fluidnozzle lacking a restriction point). The jet force 127 provides moreefficient forceful agitation of the porous filtration media, providingmore efficient particle removal as discussed below.

The restriction point may be located at any point in riser 152. In oneembodiment, the restriction point 153 is located at or adjacent toopening 152 a; in such an embodiment, the restriction point 153 orelements creating the restriction point may contact, at least partially,opening 151 or scouring fluid inlet pipe 119. In another embodiment, therestriction point is located at or adjacent to end 152 b. In anotherembodiment, restriction point 153 is located at a position in betweenends 152 a and 152 b. The restriction point may also be placed at thecenter-line of riser 152 or left or right of the centerline of riser152. Furthermore, the length of the domain having a reduced crosssectional area created by restriction point 153 may vary. In certainaspects, the length of the domain is a single point within riser 152(for example, see FIG. 3D, right panel). In certain aspects, the lengthof the domain extends only along a portion of the length of riser 152(for example, see FIG. 3E, left panel). In certain aspects, the lengthof the domain extends along all or substantially all the length of riser152 as measured from the point at which the cross sectional area isreduced towards second end 152 b (for example, see FIG. 3E, rightpanel).

The restriction point 153 may be provided in a number of ways. In afirst aspect, the restriction point 153 is provided by providing one ormore flanges 152 e as illustrated in FIG. 3D (right side). FIG. 3D shows2 flanges 152 e positioned at the bottom of riser 152 at opening 152 a,however 1 longer flange 152 e may be used to create restriction point153 and the placement of the flange(s) 152 e may be placed at otherlocations in riser 152 as discussed herein.

In another aspect, the restriction point 153 is provided by restrictor154 (shown in FIG. 3D, left side), which comprises a body 155 with anopening 156 through body 155 (which serves as restriction point 153). Inthis aspect, the riser 152 is in fluid communication with opening 151through opening 156 of restrictor 154. The restrictor 154 may beprovided as a separate component joined to either end of the riser 152any may contact and/or be joined to opening 151 as well. Alternatively,the restrictor 154 may be supplied as an integral part of the scouringfluid nozzle 150 by inclusion in riser 152. As shown in FIG. 3D, therestrictor 154 is placed away from end 152 a; however, the restrictor154 may be placed at other locations in riser 152 as discussed herein.

In still another aspect, the restriction point 153 is provided by anozzle, indicated in FIG. 3E as 157. Nozzle 157 creates opening 158which serves as restriction point 153. As shown in FIG. 3E, the nozzle157 is placed away from end 152 a; however, the nozzle 157 may be placedat other locations in riser 152 as discussed herein.

In another aspect, the restriction point 153 is provided by an inwarddeflection 160 of one or both of the side walls 152 d of riser 152 (FIG.3F, left side). In such an aspect, no additional element (for example,nozzle 157) is required to provide the restriction point 153. As shownin FIG. 3F, the inward deflection 160 is placed away in the middleportion of riser 152; however, the inward deflection 160 may be placedat other locations in riser 152 as discussed herein.

In still another aspect, riser 152 is provided with passage 152 c thathas a cross sectional area less than that of opening 151 (FIG. 3F, rightpanel). In this aspect, the passage 152 c serves as the restrictionpoint 153. The riser 152 is secured to the scouring fluid inlet pipe 119to create restriction 153. Various methods may be used to secure riser152, with FIG. 3E showing riser 152 being secured by legs 162 (which maybe welded, for example, to scouring fluid inlet pipe 119).

In still another aspect, the restriction point 153 is provided by anymeans described herein and the domain of the restriction point 153continues along at least a portion of passage 152 c. An exemplaryembodiment, is shown in FIG. 3E, right panel, where restriction point isprovided by nozzle 157 and the domain of the restriction point continuesto the end 152 b of riser 152 (through sidewalls 159). In certainaspects, the increased length of the domain of the restriction pointaids in maintaining the jet force 127 of the SF 123.

In the above aspects, the smaller the ratio of the cross sectional areaof restriction point to opening 151 in the scouring fluid inlet pipe119, the greater the jet force 127 of SF 123. In one embodiment, theratio is less than 1.0 but greater than 0. In one embodiment, the ratiois less than or equal to 0.8, such as 0.7, 0.6, 0.5, 0.4 or 0.3, butgreater than 0. In another embodiment, the ratio is from 0.3 to 0.8(inclusive of the endpoints of the range). The various configurationsfor forming the restriction point may be varied (such as for example,varying the length of flange(s) 152 e) to achieve the desired ratio.

The scouring fluid nozzles 150 as provided herein may be used inoriginal construction of a filtration unit or may be used to retrofit anexisting filtration unit to employ the directed scouring fluid method.Because the restriction point 153 is a component of the scouring fluidnozzle 150 (even though the restriction point 153 may contact opening151 or other portions of the scouring fluid inlet pipe 119), such aretrofit is possible. For example, an existing filtration unit may beretrofitted by securing one of more scouring fluid nozzles 150 to theexisting scouring fluid inlet pipe. Methods for the securing of variouscomponents, such as plastics and metals for example, are known in theart any may be used. Therefore, the present disclosure also provides ascouring fluid nozzle 150 in the embodiments described above as aseparate and independent component. Furthermore, the scouring fluidinlet pipe along with one or more associated scouring fluid nozzles mayalso be provided as a replacement part in a retrofit operation.Therefore, the present disclosure also provides a scouring fluid inletpipe with at least one associated scouring fluid nozzle 150 in theembodiments described above as a separate and independent component.

The end 152 b of scouring fluid nozzle 150 is placed in close proximityto the filter bed or when a bottom plate (such as 107) is present, aperforation 113 b in bottom plate 107, to direct the SF 123 throughperforation 113 b and into filter media bed 109. In one embodiment, theend 152 b may extend at least partially through perforation 113 b. Inanother embodiments, the end 152 b is positioned just below bottom plate107. It is preferable to align the riser 152 of the scouring fluidnozzle 150 such that the mid-point of the diameter of the riser 152 isaligned approximately with the midpoint of the opening in perforation113 b to provide an unobstructed flow of SF 123 through opening 113 b.The SF 123 may be delivered at a variety of pressures. In oneembodiment, the scouring fluid is delivered at between 4 and 16 lbspressure. In another embodiment, the scouring fluid is delivered atbetween 4 and 8 lbs pressure. In another embodiment, the scouring fluidis delivered at between 7 to 16 lbs pressure.

As discussed herein, the SF 123 is released with a jet force 127 as itexits the scouring fluid nozzle 150 imparting additional energy to theSF 123 (the jet force 127). The SF 123 will also be subject to the samebuoyant force as described for the prior art embodiment above.Therefore, by use of scouring fluid nozzle 150, the SF 123 is deliveredwith greater force to the expanded filter media bed 109, resulting in agreater forceful agitation of the filter media bed 109.

In one embodiment, the SF 123 is compressed air, however other SFs maybe used provided that the SF employed has a density that is less thanthe PRF and rises in the PRF. In one embodiment the influent streamitself serves as the PRF. In another embodiment, the PRF is water. Thewater may be potable water or may be water that is in need offiltration. As discussed herein and as is known in the art, other SFsand PRFs may be used in combination.

The materials from which the various components of the filtration unit100 are constructed may be varied as is known in the art. In oneembodiment, the riser 152 is made of the same material as the scouringfluid inlet pipe 119 and the restrictor 154, for example a metalmaterial. In another embodiment, the riser 152 is constructed from aflexible material, such as a polymer, plastic or rubber provided thatthe flexible material has a rigidity sufficient to maintain the riser inan upright position when SF 123 is flowing through riser 152.

In the arrangement described above, the number of scouring fluid nozzles150 present on scouring fluid inlet pipe 119 may vary. Furthermore, notevery perforation 113 b is required to have a scouring fluid nozzle 150in proximity thereto. The size and configuration of the filtration unitwill determine in part how many scouring fluid nozzles 150 are present.In one embodiment, 4 to 24 scouring fluid nozzles are present onscouring fluid inlet pipe 119. In another embodiment, 1 to 5 scouringfluid nozzles are present on scouring fluid inlet pipe 119. In anotherembodiment, 5 to 10 scouring fluid nozzles are present on scouring fluidinlet pipe 119. In another embodiment, 11 to 15 scouring fluid nozzlesare present on scouring fluid inlet pipe 119. In another embodiment, 16to 20 scouring fluid nozzles are present on scouring fluid inlet pipe119. In another embodiment, 20 to 24 scouring fluid nozzles are presenton scouring fluid inlet pipe 119.

As shown in FIG. 3B, the filtration unit may contain 1 or more than 1scouring fluid inlet pipes 119. Furthermore, when a single scouringfluid inlet pipe is present, the scouring fluid inlet pipe may becontain 1 or more than one branches joined to a central pipe if desiredwith the scouring fluid nozzles placed on each of the branches and/orthe central pipe. Such embodiments may provide for more evendistribution of the SF into the filter bed. In one embodiment, thefiltration unit comprises 1 to 8 scouring fluid inlet pipes 119, witheach scouring fluid inlet pipe 119 having 4 to 24 scouring fluid nozzles150. When multiple scouring fluid inlet pipes are present, each may beassociated with its own source of SF or multiple scouring fluid inletpipes may share a common source of SF.

Further, the scouring fluid nozzles 150 present on a particular scouringfluid inlet pipe or within the filtration unit are not required to bethe same. In certain aspects, the restriction point 153 of the scouringfluid nozzles 150 may be created by different methods. In certainaspects, the ratio of the ratio of the cross sectional area ofrestriction point 153 to opening 151 in the scouring fluid inlet pipe119 may be varied for individual scouring fluid nozzles 150 present on aparticular scouring fluid inlet pipe 119 or within the filtration unit.In certain aspects, the length of the domain having a reduced crosssectional area created by restriction point 153 may be varied forindividual scouring fluid nozzles 150 present on a particular scouringfluid inlet pipe 119 or within the filtration unit. Combinations of theforegoing may also be provided (for example, the ratio of the crosssectional area of restriction point 153 to opening 151 in the scouringfluid inlet pipe 119 and the length of the domain having a reduced crosssectional area created by restriction point 153 may be varied forindividual scouring fluid nozzles 150 present on a particular scouringfluid inlet pipe 119 or within the filtration unit).

Furthermore, scouring fluid nozzles 150 may be arranged with differentconfigurations on one or more of scouring fluid inlet pipes 119 orwithin the filtration unit on one or more of scouring fluid inlet pipes119 to provide a desired pattern of forceful agitation of the porousfiltration media by providing a gradient of jet force 127 created by thedifferent configurations of the scouring fluid nozzles 150. As anexample, in FIG. 3G upper panel, scouring fluid nozzles 150 a to 150 fare provided on a single scouring fluid inlet pipe 119, with at least aportion of the scouring fluid nozzles 150 a to 150 f providing adifferent jet force 127 to create a gradient of jet force 127 in thefilter media bed 109. The differences in jet force may be created in anymanner described herein (for example, by varying the ratio of the crosssectional area of restriction point 153 to opening 151 in the scouringfluid inlet pipe 119 and/or the length of the domain having a reducedcross sectional area created by restriction point 153). As seen in FIG.3G upper panel, the jet force 127 in this example is the least nearclosed end and is greatest as the distance from end 120 increases. Thejet force 127 thereby creates a gradient to provide a desired pattern offorceful agitation indicated by arrows 125. The scouring fluid nozzles150 on additional scouring fluid inlet pipes 119 in the filtration unitmay each have the same configuration and produce the same jet force tomaintain the jet force gradient across the filtration unit or may beconfigured differently to produce a different jet force gradient (or noadditional gradient) across the filtration unit.

A jet force 127 gradient may also be produced between different scouringfluid inlet pipes 119 as shown in FIG. 3G, lower panel. In this example,scouring fluid inlet pipes 119 a to 119 d are provided with scouringnozzles 150 a to 150 d, with at least a portion of the scouring fluidnozzles 150 a to 150 d providing a different jet force 127 to create agradient of jet force in the filter media bed 109. As above, thedifferences in jet force may be created in any manner described herein.As seen in FIG. 3G lower panel, the jet force 127 in this example is thegreatest near side wall 102 and is decreased as the distance from sidewall 102 increases. The jet force 127 thereby creates a gradient toprovide a desired pattern of forceful agitation indicated by arrows 125.The scouring fluid nozzles 150 on each scouring fluid inlet pipe 119 mayeach have the same configuration and produce the same jet force andmaintain the jet force gradient along the length of the scouring fluidinlet pipe 119 or may be configured differently to produce a differentjet force gradient along the length of the scouring fluid inlet pipe119.

The above examples are illustrative only and other jet force gradientsmay be created.

The operation of the unit 100 is essentially the same as for the priorart device described above and illustrated in FIGS. 1 and 2, with theexception of the operation of the wash cycle. FIG. 3A shows the improvedfiltration unit 100 in the wash cycle with the upper plate 105 movedupward to provide an expanded filter media bed 109. During the washcycle, if the influent fluid is serving as the PRF 130, then the flow ofthe influent fluid continues, but typically at a reduced rate. Duringthe wash cycle, if the influent fluid is not serving as the PRF, theflow of influent fluid is terminated and flow of PRF 130 is initiatedand PRF 130 is introduced to the filtration unit 100 through influentpipe 115 (flowing in the direction of arrow 132). In another embodiment,the PRF 130 enters the filtration unit 100 through a separate, dedicatedPRF influent nozzle. The SF 123 is released under the expanded filtermedia bed 109 through scouring fluid inlet pipe 119 and scouring fluidnozzles 150. As the SF 123 rises into the filter media bed, it passesthrough perforations 113 b in the lower plate 107 and agitates theindividual porous filtration media units in the expanded filter mediabed 109. This agitation, exemplified by the arrows 125, createscollisions between individual porous filtration media with one anotherand with the housing 102 and other components of the unit 100. Thesecollisions cause the captured contaminant particles 121 b to be releasedfrom the porous filtration media yielding released contaminant particles121 c which are carried by the PRF 130 away from the filter media bed109 and through effluent pipe 117 (the influent fluid effluent pipe 116is shown as closed). Due to the increased force with which SF 123 isdelivered to the expanded filter media bed 109, the agitation of theexpanded filter media bed 109 is significantly increased.

The efficiency of a wash cycle and the degree of cleaning (DOC) of theporous filtration media units is proportional to the magnitude of theforceful agitation (FA) of the individual porous filtration media unitsin the expanded filter media bed. As the FA increases, the magnitude ofthe impacts (MOI), which includes the number of impacts and the force ofthe individual impacts, of the porous filtration media units with eachother, and with the components of the filtration unit (the vessel wallsand upper and lower plates) increases. The force of these impacts freesthe captured contaminant particles from the porous filtration mediaunits, which allows the particles to be removed by the PRF that isflowing through the expanded filter media bed. The greater the number ofimpacts and the greater the MOI with which these impacts occur, thegreater the DOC. A greater DOC allows for a shorter wash cycle timeand/or the use of less PRF.

Mathematically, this can be stated as:DOC∝MOI and MOI∝FA

Therefore:DOC∝FA  (Equation 1)

In the prior art device described above, (see FIGS. 1 and 2), the FA istotally dependent on the lighter density SF rising up through theheavier PRF (i.e., the buoyancy force, (BF). As the BF increases so doesthe FA.

Mathematically, for the prior art device, this can be represented asshown in Equation 2:FA∝BF  (Equation 2)

As discussed above, in the new arrangement, (see FIGS. 3A-C), the SFexits the scouring fluid nozzles with increased velocity. Therefore, theSF has a jet force (JF) resulting from the new arrangement. Since the BFacting on the SF rising in the PRF is still at work, for the newarrangement, the FA is proportional to the JF plus the BF.

Mathematically, this can be represented as shown in Equation 3 (whereFA_(N) is the forceful agitation induced by the directed scouring fluidmethod):FA_(N)∝JF+BF  (Equation 3)

Since JF and BF are both positive values, JF+BF>BF. Therefore, usingfiltration unit shown in FIGS. 3A-3D results in a FA that is greater ascompared to the prior art device described above. As FA is directlyproportional to the DOC, the DOC for the filtration unit shown in FIGS.3A-3D is greater than the DOC as compared to the DOC for the prior artdevice described above. Mathematically, this can be represented as shownin Equations 4 and 5 (where FA is the forceful agitation induced by theprior art device, DOC is the degree of cleaning achieved by the priorart device, FA_(N) is the forceful agitation induced by the scouringfluid arrangement and DOC_(N) is the degree of cleaning achieved by thedirected scouring fluid arrangement);FA_(N)>FA  (Equation 4)DOC_(N)>DOC  (Equation 5)

Therefore, the directed scouring fluid method and the filtration unitshown in FIGS. 3A-3F incorporating the directed scouring fluid methodresults in a greater efficiency in the wash cycle and DOC as compared tothe prior art device described herein.

As a result of the increased efficiency and DOC, the directed scouringfluid method and improved filtration unit provides benefits over thefiltration units of the prior art. In one embodiment, the method and theimproved filtration unit 100 results in a higher DOC of the porousfiltration media as compared to prior art. In another embodiment, themethod and the improved filtration unit 100 provides a DOC of the porousfiltration media that approaches the DOC obtained when the porousfiltration media was subject to a stringent wash using chemicaladditives, such as detergents. In another embodiment, the method and theimproved filtration unit 100 provides a DOC of the porous filtrationmedia that is comparable to that obtainable in the prior art, but with awash cycle time that is less in duration than that of the prior art (forexample, 20% less or greater, 25% less of greater, 30% less or greater,35% less or greater, 40% less or greater, 45% less or greater or 50%less or greater or for example, less than 20 minutes, less than 18minutes, less than 16 minutes, less than 14 minutes or 12 minutes orless). In another embodiment, the improved filtration unit 100 providesan increased rate of cleaning of the porous filtration media (forexample, a greater DOC in the first 10 minutes of a wash cycle).

In a particular embodiment, the directed scouring fluid method andimproved filtration unit removes at least 50% of the trapped contaminantparticles from the filtration media units, including porous filtrationmedia units, during a wash cycle. In such an embodiment, the duration ofthe wash cycle may be less than or equal to 25 minutes, 20 minutes, 15minutes or 10 minutes.

In another particular embodiment, the directed scouring fluid method andimproved filtration unit removes at least 60% of the trapped contaminantparticles from the filtration media units, including porous filtrationmedia units, during a wash cycle. In such an embodiment, the duration ofthe wash cycle may be less than or equal to 25 minutes, 20 minutes, 15minutes or 10 minutes.

In a particular embodiment, the directed scouring fluid method andimproved filtration unit removes at least 70% of the trapped contaminantparticles from the filtration media units, including porous filtrationmedia units, during a wash cycle. In such an embodiment, the duration ofthe wash cycle may be less than or equal to 30 minutes or 25 minutes.

In a particular embodiment, the directed scouring fluid method andimproved filtration unit removes at least 80% of the trapped contaminantparticles from the filtration media units, including porous filtrationmedia units, during a wash cycle. In such an embodiment, the duration ofthe wash cycle may be less than or equal to 35 minutes.

In a particular embodiment, the directed scouring fluid method andimproved filtration unit removes at least 50% of the trapped contaminantparticles from the filtration media units, including porous filtrationmedia units, during the first 10 minutes or a wash cycle. In aparticular embodiment, the directed scouring fluid method and improvedfiltration unit removes at least 50% of the trapped contaminantparticles from the filtration media units, including porous filtrationmedia units, during the first 15 minutes or a wash cycle.

Transition Plenum

The principles of the transition plenum improvement are described belowwith reference to FIGS. 4A and 4B. The concept is illustrated in thecontext of a filtration unit 100 having an upper movable plate 105.However, the principles of operation apply equally to filtration unitshaving a fixed upper plate 105 either in conjunction with a fixed lowerplate 107 or a movable lower plate 107.

As described above, during the wash cycle, the introduced SF 123 risesthrough the PRF 130, impacting the porous filtration media along theway. Eventually, the SF 123 exits the PRF 130 and enters a liquid freezone at the top of the filtration unit (160). The SF 123 exits thefiltration unit 100 through scouring fluid exit pipe 118. When the SF123 exits the PRF 130, small amounts of the PRF 130 are carried by theSF 123 upwards away from the bulk PRF 130 creating a transition zone200. In the transition zone 200 there is no clearly defined interfacebetween the SF 123 and the PRF 130. The transition zone can bevisualized by the froth (illustrated by 206) created by the action ofthe SF 123 leaving the PRF 130. The transition zone occurs only duringthe washing cycle.

In the prior art device described an illustrated in FIGS. 1-2, thetransition zone occurred only above the upper plate 5 in an area whereno porous filtration media units are present. Surprisingly, it has beenfound that by controlling the operating parameters of the filtrationunit as described herein, the location of the transition zone 200 can becontrolled such that a portion of the transition zone 200 extends belowthe upper plate 105 as well as above the upper plate 105. As a result,the porous filtration media units are present in and subject to theeffects of the transition zone 200. The area of the transition zone 200below the upper plate 105 is defined as the transition plenum 202.

In the transition plenum 202, a portion of the individual porous mediafiltration units in the filter media bed (204, shown in solid black)escape the PRF 130 and continue to travel upward (in the direction ofthe upper plate 105) in the transition plenum 202. As discussed herein,during the wash cycle the SF 123 is released under pressure and rises inthe PRF 130 and enters the filter media bed 109 where is creates aforceful agitation of the individual porous filtration media in filtermedia bed 109. As the SF 123 is lighter than the PRF 130, the SFcontinues to rise in the PRF in the form of bubbles. As the SF 123encounters the individual porous filtration media units, the buoyancy ofthe SF 123 carries the individual porous filtration media units upwardtowards the underside of the upper plate 105. As the individual porousfiltration media units move upward, a drag force is created by the PRF130 which slows the upward motion and at the same time creates a storedpotential energy in the individual porous filtration media units.

Due to the action of the SF 123, a portion of the individual porousfiltration media units reach and exit the PRF 130 and enters thetransition plenum 202. When this occurs, the drag force is eliminated orgreatly reduced, and due to the stored potential energy created by thedrag force, the individual porous filtration media units 204 exits thePRF 130 and enter the transition plenum 202 with a force and “pop” outof the PRF 130 into the transition plenum 202. The individual porousfiltration media units are propelled by this sling-shot action andimpact the upper plate 105, the side walls 102 of the filtration unit aswell as collide with one another in the transition plenum. As thecollisions occur with an increased energy in the transition plenum 202as compared to corresponding collisions in the PRF 130, the collisionsin the transition plenum 202 release an increased amount of trappedcontaminant particles 121 b as compared to the collisions occurring inthe PRF 130 increasing the amount of released contaminant particles 121c. The released contaminant particles 121 c are then carried away by thePRF 130 through effluent pipe 117 as described.

The greater the potential energy stored in the individual porousfiltration media units, the greater the energy the individual porousfiltration media units have when they exit the PRF and enter into thetransition plenum. The faster the SF 123 causes the individual porousfiltration media units to rise in the PRF 130, the greater the storedpotential energy. Therefore, when the directed scouring fluid methoddescribed herein is coupled with the creation of a transition plenum,the SF is provided with a jet force 127 (see FIG. 3B) created by thescouring fluid nozzles 150 and due to the increased force, causes theindividual porous filtration media units to rise faster in the PRF 130and increases the stored potential energy in the individual porousfiltration media units. As a result, the force of the collisions createdin the transition plenum 202 may be further increased. Therefore, in oneembodiment the directed scouring fluid method and the transition plenummethod may be used in conjunction with one another to produce increasedrelease of trapped contaminant particles in the porous filtration mediaunits. The dual use of both approaches results in a synergistic cleaningeffect in one aspect of this embodiment. In another embodiment, thetransition plenum method is used without the directed scouring fluidmethod to produce increased release of trapped contaminant particles inthe porous filtration media units

The transition plenum 202 is created by controlling one or more of theoperating parameters of the filtration unit 100. Parameters suitable forcontrolling to create the transition plenum 202 include the SF flowrate, the PRF flow rate, the relative positions of the upper and lowerplates to one another, the ratio of the height of the filter media bedfrom the filtration cycle to the wash cycle, the relative position ofthe upper plate to the particle removal fluid effluent pipe and thedistance from the top surface of the lower plate to the bottom of theinvert of the particle removal fluid effluent pipe and the distance fromthe top of the lower plate to the bottom of the upper plate during thewash cycle. The values of the individual parameters will depend in parton the characteristics of the filtration unit (for example, the volumeof the filtration unit, the dimensions of the filtration unit and thelike). The exemplary parameters below are provided for a modelfiltration unit to provide an embodiment of the operating principles.The model filtration unit has a total vertical height of 87.2 inches, acircular cross section with a diameter of 11.75 inches, a filter mediabed area of 108.4 square inches, a filter media bed depth duringfiltration of 30 inches, a filter media bed volume of 3,252 cubic inchesduring filtration and an influent stream design flow rate duringfiltration of 23 gpm. As the characteristics of the filtration unitdiffer from these of the model filtration unit, the values for theparameters below may also change.

In one aspect, the transition plenum 202 is created by proper selectionof the distance from the top of the lower plate 107 to the bottom of theinvert of the effluent pipe 117 for the PRF (the distance Z in FIG. 4A)and controlling the distance between the bottom of the upper and the topof the bulk PRF (the area where the transition plenum begins) (thedistance X in FIG. 4A). In the prior art, the distance Z for filtrationunits of the description above ranged from 72 inches to 96 inches andthe distance X did not exist. In one aspect of the transition plenummethod and device for carrying out such method, for filtration units ofthe description above the distance X ranges from 1 to 6 inches while thedistance Z ranges from 48 inches to inches, such as, but not limited to,62 inches to 72 inches. Therefore, Furthermore, in one aspect of thetransition plenum method and device for carrying out such method for thetransition plenum method and device for carrying out such method, theparticle removal effluent pipe is placed in a lower position (i.e.,closer to the lower plate 107) as compared to its corresponding positionin the devices of the prior art. If the distance Z is not properlyselected during the design of the filtration unit, the capability ofcreating a transition plenum during wash cycles will be diminished.Therefore, the present disclosure provides a filtration unit wherein thedistance Z is from 62 inches to 72 inches. In certain embodiments, thelower plate 107 may be fixed and the placement of the bottom of theinvert of the effluent pipe for the PRF located from 62 inches to 72inches from the top of the lower plate 107. In certain aspects, thelower plate 107 may be moveable allowing greater latitude in theplacement of the effluent pipe for the PRF. In the foregoing, aspects,the flow rate of the PRF and/or SF may be as described herein, with theflow of the PRF and/or SF being continuous or intermittent and thedistance Y selected as described herein.

In another aspect, the transition plenum 202 is created by controllingthe ratio of the height of the filter media bed from the filtrationcycle (H_(F)) to the wash cycle (H_(W)). In the prior art, the ratioH_(W):H_(F) was 2:1 or less. In one aspect of the transition plenummethod and device for carrying out such method, the ratio H_(W):H_(F) isgreater than or equal to 2:1. In another embodiment of the transitionplenum method and device for carrying out such method, the ratioH_(W):H_(F) is greater than or equal to 2.5:1. In another embodiment ofthe transition plenum method and device for carrying out such method,the ratio H_(W):H_(F) is greater than or equal to 3:1. In anotherembodiment of the transition plenum method and device for carrying outsuch method, the ratio H_(W):H_(F) is greater than or equal to 2:1 andless than 4:1. In another embodiment of the transition plenum method anddevice for carrying out such method, the ratio H_(W):H_(F) is in therange of greater than or equal to 2:1 and less than or equal to 3:1. Inthe foregoing, aspects, the flow rate of the PRF and/or SF may be asdescribed herein, with the flow of the PRF and/or SF being continuous orintermittent and the distances X, Y and Z selected as described herein.

In another aspect, the transition plenum 202 is created by controllingthe distance between the bottom portion of the upper plate 105 and tothe bottom of the invert (the lowest portion of the opening of theeffluent pipe) of the effluent pipe 117 (the distance Y in FIG. 4A)during the wash cycle. In one aspect, the smaller the distance Y, thelarger the transition plenum. In the prior art, the distance Y rangesfrom 20 inches to 48 inches. In one aspect of the transition plenummethod and device for carrying out such method, the distance Y is lessthan 15 inches, such as less than 10 inches or less than 6 inches. Inanother embodiment of the transition plenum method and device forcarrying out such method, the distance Y the ranges from 0 inches to 6inches. In the foregoing, aspects, the flow rate of the PRF and/or SFmay be as described herein, with the flow of the PRF and/or SF beingcontinuous or intermittent, and the distances X, and Z selected asdescribed herein.

In another aspect, the transition plenum 202 is created by controllingthe flow rate of the PRF. The flow rate is typically measured in unitsof volume/time/area, where area is the cross sectional area of filtermedia bed (such as gallons or cubic feet/minute/ft²). In the prior art,the flow rate of the PRF ranges from 10 gpm/ft² to 40 gpm/ft². In oneaspect of the transition plenum method and device for carrying out suchmethod, the flow rate of the PRF is less than gpm/ft². In anotherembodiment of the transition plenum method and device for carrying outsuch method, the flow rate of the PRF is less than 5 gpm/ft². In anotherembodiment of the transition plenum method and device for carrying outsuch method, the flow rate of the PRF ranges from 5 gpm/ft² to 10gpm/ft². In another embodiment of the transition plenum method anddevice for carrying out such method, the flow rate of the PRF isintermittent instead of continuous. In another embodiment of thetransition plenum method and device for carrying out such method, theflow rate of the PRF is less than 5 gpm/ft² or less 10 gpm/ft² and theflow rate of the PRF is intermittent. In another aspect of thetransition plenum method and device for carrying out such method, theflow rate of the PRF ranges from 5 gpm/ft² to 10 gpm/ft² and the flowrate of the PRF is intermittent. In the foregoing, aspects, the flowrate of SF may be as described herein, with the flow of the SF beingcontinuous or intermittent and the distances X, Y and Z selected asdescribed herein.

In another aspect, the transition plenum 202 is created by controllingthe flow rate of the SF. The flow rate is typically measured in units ofvolume/time/area, where area is the cross sectional area of filter mediabed (such as gallons or cubic feet/minute/ft²). In the prior art, theflow rate of the SF ranges from 10 CFM/ft² to 20 CFM/ft². In one aspectof the transition plenum method and device for carrying out such method,the flow rate of the SF is greater than CFM/ft². In another aspect ofthe transition plenum method and device for carrying out such method,the flow rate of the SF is greater than 40 CFM/ft². In another aspect ofthe transition plenum method and device for carrying out such method,the flow rate of the SF is greater than CFM/ft². In another aspect ofthe transition plenum method and device for carrying out such method,the flow rate of the SF ranges from 40 CFM/ft² to 60 CFM/ft². In anotheraspect of the transition plenum method and device for carrying out suchmethod, the flow rate of the SF ranges from 50 CFM/ft² to 60 CFM/ft². Inanother aspect of the improved art, the flow rate of the SF isintermittent instead of continuous. In another aspect of the transitionplenum method and device for carrying out such method, the flow rate ofthe SF is greater than 30 CFM/ft², such as greater than 40 CFM/ft² or 50CFM/ft², and the flow rate of the SF is intermittent. In another aspectof the transition plenum method and device for carrying out such method,the flow rate of the SF ranges from 40 CFM/ft² to 60 CFM/ft², such asfrom ranges from 50 CFM/ft² to 60 CFM/ft², and the flow rate of the SFis intermittent. In the foregoing, aspects, the flow rate of the PRF maybe as described herein, with the flow of the PRF being continuous orintermittent and the distances X, Y and Z selected as described herein.

In another aspect, the transition plenum 202 is created by controllingthe flow rate of the SF and the flow rate of the PRF in conjunction. Inthe prior art, the ratio of the flow rate of the SF to the PRF was lessthan 15 to 1. In one aspect of the transition plenum method and devicefor carrying out such method, the ratio of the flow rate of the SF tothe PRF is greater than 15 to 1, such as 20 to 1. In another aspect ofthe transition plenum method and device for carrying out such method,the ratio of the flow rate of the SF to the PRF is greater than 30 to 1.In another aspect of the transition plenum method and device forcarrying out such method, the ratio of the flow rate of the SF to thePRF is greater than 40 to 1. In another aspect of the transition plenummethod and device for carrying out such method, the ratio of the flowrate of the SF to the PRF is in the range of 20 to 1 to 50 to 1. Theflow rates of the SF and PRF discussed above are used in certainembodiments of the foregoing, with the flow of the SF and/or PRF beingcontinuous or intermittent.

In another aspect, the transition plenum 202 is created by controllingthe flow rate of the SF, the flow rate of the PRF and the distance Y inconjunction with one another. In one aspect of the transition plenummethod and device for carrying out such method, the flow rate of the SFis greater than the flow rate of the PRF and the distance Y is less than15 inches. For example, in a particular aspect the flow rate of the SFmay be in the range of 50 to 60 CFM/ft², the flow rate of the PRF may bein the range of 5 to 10 gpm/ft². In another particular aspect, the flowrate of the SF may be in the range of 15 to 60 CFM/ft², the flow rate ofthe PRF may be in the range of 5 to 15 gpm/ft². In another aspect of thetransition plenum method and device for carrying out such method, theratio of the flow rate of the SF to the PRF is greater than 20 to 1 andthe distance Y is less than 15 inches. In another aspect of thetransition plenum method and device for carrying out such method, theratio of the flow rate of the SF to the PRF is greater than 40 to 1 andthe distance Y is less than 6 inches.

In another aspect, the transition plenum 202 is created by controllingthe flow rate of the SF, the flow rate of the PRF, the distance Z andthe distance Y in conjunction with one another. In one aspect of thetransition plenum method and device for carrying out such method, theflow rate of the SF is greater than the flow rate of the PRF, thedistance Z is in the range of 48 inches to 60 inches and the distance Yis less than 15 inches. For example, in a particular aspect the flowrate of the SF may be in the range of 50 to 60 CFM/ft², the flow rate ofthe PRF may be in the range of 5 to 10 gpm/ft². In another particularaspect, the flow rate of the SF may be in the range of 15 to 60 CFM/ft²,the flow rate of the PRF may be in the range of 5 to 15 gpm/ft². Inanother aspect of the transition plenum method and device for carryingout such method, the ratio of the flow rate of the SF to the PRF isgreater than 20 to 1, the distance Z is in the range of 54 inches to 60inches and the distance Y is less than 15 inches. In another aspect ofthe transition plenum method and device for carrying out such method,the ratio of the flow rate of the SF to the PRF is greater than 40 to 1,the distance Z is in the range of 54 inches to 60 inches and thedistance Y is less than 6 inches.

As shown in FIG. 4A, the effluent pipe 117 is located above the upperplate 105. However, in an alternate embodiment, the effluent pipe 117 islocated below the upper plate as shown in FIG. 4B (showing a magnifiedview of the transition plenum 202. In this embodiment, the majority ofthe transition zone 200 is located below the upper plate 105, making thetransition plenum 202 the majority of the transition zone 200 in thisembodiment. In FIG. 4B, the same reference numbers identify the samecomponents as in FIG. 4A. FIG. 4B shows in greater detail the collisionsbetween the individual porous filtration media units 204 in thetransition plenum 202 with the generation of released contaminantparticles 121 c. other than the placement of the effluent pipe 117 belowthe upper plate 105, the operation of this embodiment is the same asthat described for FIG. 4A.

Therefore, in one embodiment, the present disclosure provides animproved filtration unit having an effluent pipe 117 position belowupper plate 105. An embodiment of a filtration device incorporating thedirected scouring fluid method and having an effluent pipe 117 below theupper plate 105 is shown in FIG. 4C. The reference numbers in FIG. 4Ccorrespond to the reference numerals used in FIGS. 3A-3D and FIGS.4A-4B.

Certain Embodiments of the Apparatus for Conducting Directed ScouringFluid Method

The present disclosure also provides for an apparatus for conducting thedirected scouring fluid method. In one embodiment, the apparatuscomprises a scouring fluid inlet pipe comprising a plurality of openingson a top portion of the scouring fluid inlet pipe and a scouring fluidnozzle in fluid communication with at least one of the openings on thescouring fluid inlet pipe, wherein the scouring fluid nozzle comprises arestriction point. In one aspect, the scouring fluid nozzles 150comprise a riser 152 having an open first end 152 a and an open secondend 152 b joined by side walls 152 d and forming a passage 152 c, and arestriction point 153. Any embodiment of the scouring fluid nozzle 150described herein may be used.

In the foregoing aspect, the restriction point may be located at anypoint in riser 152. In one embodiment, the restriction point 153 islocated at or adjacent to opening 152 a; in such an embodiment, therestriction point 153 may also contact, at least partially, opening 151.In another embodiment, the restriction point is located at or adjacentto end 152 b. In another embodiment, restriction point 153 is located ata position in between ends 152 a and 152 b. The restriction point mayalso be placed at the center-line of riser 152 or left or right of thecenterline of riser 152. Further, in the foregoing aspects, the ratio ofthe cross sectional area of restriction point 153 to opening 151 in thescouring fluid inlet pipe 119 is less than 1.0 but greater than 0, suchas less than or equal to 0.8, such as 0.7, 0.6, 0.5, 0.4 or 0.3. Inanother embodiment, the ratio of the diameter of restriction point 153to opening 151 is from 0.3 to 0.8.

In particular embodiments of the foregoing aspects, the scouring fluidnozzles 150 may be selected from the embodiments below (with referencenumbers corresponding to FIGS. 3D-3F).

In one embodiment, the scouring fluid nozzle 150 comprises a riser 152having an open first end 152 a and an open second end 152 b joined byside walls 152 d and forming a passage 152 c and one or more flanges 152e (which provide the restriction point 153). As discussed herein, theplacement of the flange(s) 152 e may be placed at various locations inriser 152.

In another embodiment, the scouring fluid nozzle 150 comprises a riser152 having an open first end 152 a and an open second end 152 b joinedby side walls 152 d and forming a passage 152 c and a restrictor 154,the restrictor comprising a body 155 with an opening 156 through body155 (which serves as restriction point 153). In this aspect, the riser152 is in fluid communication with opening 151 through opening 156 ofrestrictor 154. As discussed herein, the placement of the restrictor 154may be placed at various locations in riser 152.

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c and a nozzle 157(which serves as restriction point 153).

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c, with at leastone of side walls 152 d having an inward deflection 160 (which serves asrestriction point 153).

The pinch point may be created as discussed herein, such as by a nozzle157 or inward deflection 160. As discussed herein, the nozzle 157 orinward deflection 160 may be placed at various locations in riser 152.

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c, wherein theriser 152 is provided with passage 152 c that has a diameter less thanthat of opening 151 (which serves as the restriction point 153). Theriser 152 is secured to the scouring fluid inlet pipe 119 as discussedherein, such as by legs 162.

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c and a restrictionpoint 153, wherein the diameter of passage 152 c continues to berestricted for at least a portion of the distance between restrictionpoint 153 to end 152 b.

Certain Embodiments of the Filtration Unit

The filtration unit has been described above in the methods for carryingout the specific methods. As discussed, the configuration of thefiltration unit may vary depending on the cleaning method employed andother factors. All such descriptions are intended to be descriptions ofthe filtration unit. The description below discusses exemplaryconfigurations of the filtration device and is not intended to belimiting.

In one aspect, the filtration unit 100 adapted to carry out the directedscouring fluid method comprises a scouring fluid inlet pipe 119comprising a plurality of openings 151 on a top portion of the scouringfluid inlet pipe 119 and a scouring fluid nozzle 150 in fluidcommunication with at least one of the openings 151, and at least one ofa housing 102, an upper plate 105 containing a plurality of perforations113 a, a filter media bed 109 comprising a plurality of porousfiltration media units, influent pipe 115 (which may serve as theinfluent pipe for both the influent fluid 111 and the PRF 130) and aneffluent pipe 117 for the PRF 130. In one aspect, the scouring fluidnozzles 150 comprise a riser 152 having an open first end 152 a and anopen second end 152 b joined by side walls 152 d and forming a passage152 c, and a restriction point 153. Any embodiment of the scouring fluidnozzle 150 described herein may be used.

Such filtration unit may also further comprise a bottom plate 107containing a plurality of perforations 113 b, an additional effluentpipe, an additional influent pipe, a plate actuator to moveably engagedwith at least one of the upper 105 or lower 107 plates to providemovement of at least one of plates 105 and 107 relative to anotherportion of the filtration unit and/or to one another and other accessorycomponents common in filtration units.

In another aspect, the filtration unit 100 adapted to carry out thetransition plenum method comprises an upper plate 105 containing aplurality of perforations 113 a and an effluent pipe 117 for the PRF130, wherein the effluent pipe 117 is located above the upper plate 105and the distance Y is less than 15 inches, such as 6 inches or less, andat least one of a housing 102, a filter media bed 109 comprising aplurality of porous filtration media units, influent pipe (which mayserve as the influent pipe for both the influent fluid 111 and the PRF130).

Such filtration unit may also further comprise scouring fluid inlet pipe119 comprising a plurality of scouring fluid nozzles 150, a bottom plate107 containing a plurality of perforations 113 b, an additional effluentpipe, an additional influent pipe, a plate actuator to moveably engagedwith at least one of the upper 105 or lower 107 plates to providemovement of at least one of plates 105 and 107 relative to anotherportion of the filtration unit and/or to one another and other accessorycomponents common in filtration units. In one aspect, the scouring fluidnozzles 150 comprise a riser 152 having an open first end 152 a and anopen second end 152 b joined by side walls 152 d and forming a passage152 c, and a restriction point 153. Any embodiment of the scouring fluidnozzle 150 described herein may be used.

In another aspect, the filtration unit 100 adapted to carry out thetransition plenum method comprises an upper plate 105 containing aplurality of perforations 113 a and an effluent pipe 117 for the PRF130, wherein the effluent pipe 117 is located below the upper plate 105,and at least one of a housing 102, a filter media bed 109 comprising aplurality of porous filtration media units, influent pipe 115 (which mayserve as the influent pipe for both the influent fluid 111 and the PRF130).

Such filtration unit may also further comprise scouring fluid inlet pipe119 comprising a plurality of scouring fluid nozzles 150, a bottom plate107 containing a plurality of perforations 113 b, an additional effluentpipe, an additional influent pipe, a plate actuator to moveably engagedwith at least one of the upper 105 or lower 107 plates to providemovement of at least one of plates 105 and 107 relative to anotherportion of the filtration unit and/or to one another and other accessorycomponents common in filtration units. In one aspect, the scouring fluidnozzles 150 comprise a riser 152 having an open first end 152 a and anopen second end 152 b joined by side walls 152 d and forming a passage152 c, and a restriction point 153. Any embodiment of the scouring fluidnozzle 150 described herein may be used.

In another aspect, the filtration unit adapted to carry out the directedscouring fluid method and the transition plenum method comprises ascouring fluid inlet pipe 119 comprising a plurality of openings 151 ona top portion of the scouring fluid inlet pipe 119 and a scouring fluidnozzle 150 in fluid communication with at least one of the openings 151,an upper plate containing a plurality of perforations 113 a and aneffluent pipe 117 for the PRF 130, wherein the effluent pipe 117 islocated above the upper plate 105 and the distance Y is less than 15inches and at least one of a housing 102, a filter media bed 109comprising a plurality of porous filtration media units, and influentpipe 115 (which may serve as the influent pipe for both the influentfluid 111 and the PRF 130). In one aspect, the scouring fluid nozzles150 comprise a riser 152 having an open first end 152 a and an opensecond end 152 b joined by side walls 152 d and forming a passage 152 c,and a restriction point 153. Any embodiment of the scouring fluid nozzle150 described herein may be used.

Such filtration unit may also further comprise a bottom plate 107containing a plurality of perforations 113 b, an additional effluentpipe, an additional influent pipe, a plate actuator to moveably engagedwith at least one of the upper 105 or lower 107 plates to providemovement of at least one of plates 105 and 107 relative to anotherportion of the filtration unit and/or to one another and other accessorycomponents common in filtration units.

In another aspect, the filtration unit adapted to carry out the directedscouring fluid method and the transition plenum method comprises ascouring fluid inlet pipe 119 comprising a plurality of openings 151 ona top portion of the scouring fluid inlet pipe 119 and a scouring fluidnozzle 150 in fluid communication with at least one of the openings 151,an upper plate containing a plurality of perforations 113 a and aneffluent pipe 117 for the PRF 130, wherein the effluent pipe 117 islocated below the upper plate 105 and at least one of a housing 102, afilter media bed 109 comprising a plurality of porous filtration mediaunits and influent pipe 115 (which may serve as the influent pipe forboth the influent fluid 111 and the PRF 130). In one aspect, thescouring fluid nozzles 150 comprise a riser 152 having an open first end152 a and an open second end 152 b joined by side walls 152 d andforming a passage 152 c, and a restriction point 153. Any embodiment ofthe scouring fluid nozzle 150 described herein may be used.

Such filtration unit may also further comprise a bottom plate 107containing a plurality of perforations 113 b, an additional effluentpipe, an additional influent pipe, a plate actuator to moveably engagedwith at least one of the upper 105 or lower 107 plates to providemovement of at least one of plates 105 and 107 relative to anotherportion of the filtration unit and/or to one another and other accessorycomponents common in filtration units.

In the foregoing aspects, the restriction point may be located at anypoint in riser 152. In one embodiment, the restriction point 153 islocated at or adjacent to opening 152 a; in such an embodiment, therestriction point 153 may also contact, at least partially, opening 151.In another embodiment, the restriction point is located at or adjacentto end 152 b. In another embodiment, restriction point 153 is located ata position in between ends 152 a and 152 b. The restriction point mayalso be placed at the center-line of riser 152 or left or right of thecenterline of riser 152. Further, in the foregoing aspects, the ratio ofthe cross sectional area of restriction point 153 to opening 151 in thescouring fluid inlet pipe 119 is less than 1.0 but greater than 0, suchas less than or equal to 0.8, such as 0.7, 0.6, 0.5, 0.4 or 0.3. Inanother embodiment, the ratio of the diameter of restriction point 153to opening 151 is from 0.3 to 0.8.

In particular embodiments of the foregoing aspects, the scouring fluidnozzles 150 may be selected from the embodiments below (with referencenumbers corresponding to FIGS. 3D-3F).

In one embodiment, the scouring fluid nozzle 150 comprises a riser 152having an open first end 152 a and an open second end 152 b joined byside walls 152 d and forming a passage 152 c and one or more flanges 152e (which provide the restriction point 153). As discussed herein, theplacement of the flange(s) 152 e may be placed at various locations inriser 152.

In another embodiment, the scouring fluid nozzle 150 comprises a riser152 having an open first end 152 a and an open second end 152 b joinedby side walls 152 d and forming a passage 152 c and a restrictor 154,the restrictor comprising a body 155 with an opening 156 through body155 (which serves as restriction point 153). In this aspect, the riser152 is in fluid communication with opening 151 through opening 156 ofrestrictor 154. As discussed herein, the placement of the restrictor 154may be placed at various locations in riser 152.

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c and a nozzle 157(which serves as restriction point 153).

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c, with at leastone of side walls 152 d having an inward deflection 160 (which serves asrestriction point 153).

The pinch point may be created as discussed herein, such as by a nozzle157 or inward deflection 160. As discussed herein, the nozzle 157 orinward deflection 160 may be placed at various locations in riser 152.

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c, wherein theriser 152 is provided with passage 152 c that has a diameter less thanthat of opening 151 (which serves as the restriction point 153). Theriser 152 is secured to the scouring fluid inlet pipe 119 as discussedherein, such as by legs 162.

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c and a restrictionpoint 153, wherein the diameter of passage 152 c continues to berestricted for at least a portion of the distance between restrictionpoint 153 to end 152 b.

In the foregoing aspects, when a scouring fluid inlet pipe 119 isprovided the filtration unit may contain 1 or more than 1 scouring fluidinlet pipes 119. In one embodiment, the filtration unit comprises 1 to 8scouring fluid inlet pipes 119. When multiple scouring fluid inlet pipesare present, each may be associated with its own source of SF ormultiple scouring fluid inlet pipes may share a common source of SF. Inthe foregoing aspects, the number of scouring fluid nozzles 150 presenton scouring fluid inlet pipe 119 may vary (and when multiple scouringfluid inlet pipes are present, the number of scouring fluid nozzles oneach may vary). Furthermore, not every perforation 113 b is required tohave a scouring fluid nozzle in proximity thereto. The size andconfiguration of the filtration unit will determine in part how manyscouring fluid nozzles 150 are present. In one embodiment, 4 to 24scouring fluid nozzles are present on scouring fluid inlet pipe 119. Inanother embodiment, 1 to 5 scouring fluid nozzles are present onscouring fluid inlet pipe 119. In another embodiment, 5 to 10 scouringfluid nozzles are present on scouring fluid inlet pipe 119.

Furthermore, in the foregoing aspects, as discussed above the scouringfluid nozzles may be arranged with different configurations on one ormore of scouring fluid inlet pipes or within the filtration unit on oneor more of scouring fluid inlet pipes 119 to provide a desired patternof forceful agitation of the porous filtration media by providing agradient of jet force 127 created by the different configurations of thescouring fluid nozzles 150 as shown in FIG. 3G (upper and lower panels).

Methods of Use

The present disclosure also provides methods of using the filtrationdevices and apparatus disclosed herein.

In one aspect, the present disclosure provides for a method of carryingout a wash cycle in a filtration device utilizing the directed scouringfluid method as described herein. Such method may achieve one or more ofthe benefits discussed herein.

In one embodiment of this aspect, the apparatus comprises a scouringfluid inlet pipe comprising a plurality of openings on a top portion ofthe scouring fluid inlet pipe and a scouring fluid nozzle in fluidcommunication with at least one of the openings on the scouring fluidinlet pipe, wherein the scouring fluid nozzle comprises a restrictionpoint. In one aspect, the scouring fluid nozzles 150 comprise a riser152 having an open first end 152 a and an open second end 152 b joinedby side walls 152 d and forming a passage 152 c, and a restriction point153. Any embodiment of the scouring fluid nozzle 150 described hereinmay be used.

In another aspect, the present disclosure provides for a method forcarrying out a wash cycle in a filtration device, the filtration devicecomprising a filter bed of porous filtration media units and a scouringfluid inlet pipe comprising a plurality of openings on a top portion ofthe scouring fluid inlet pipe and a scouring fluid nozzle incommunication with at least one of the openings on the scouring fluidinlet pipe, wherein the method comprises the step of directing ascouring fluid from the scouring fluid nozzle into the filter bed,wherein the scouring fluid nozzles comprise a restriction point toprovide a jet force to the scouring fluid.

The above configurations are exemplary in nature only and anyconfiguration of the filtration device described for use in the directedscouring fluid method may be used with the methods described herein.

Such method comprises providing a source of the SF, wherein the scouringfluid inlet pipe is in communication with the source for the SF anddirecting the SF through the described scouring fluid inlet pipes intothe filter bed, wherein the SF has jet force generated by the scouringfluid nozzles. The method may further comprise providing a source of PRFand directing the PRF into the filter bed as described herein. Themethod may still further comprise providing a blower for directing theSF and a pump for directing the PRF. In certain embodiments, thescouring fluid is compressed air. In certain embodiments, the particleremoval fluid is water. Any of the various flow rates for the SF and/orPRF as described for the directed scouring fluid method may be used insuch method.

In one aspect, the present disclosure provides for a method for carryingout a wash cycle in a filtration device comprising utilizing anapparatus for conducting the transition plenum method as describedherein.

In one embodiment of this aspect, the filtration unit comprises an upperplate 105 containing a plurality of perforations 113 a and an effluentpipe 117 for the PRF 130, wherein the effluent pipe 117 is located abovethe upper plate 105 and the distance Y is less than 15 inches, such as 6inches or less. The filtration device for conducting the transitionplenum method may further comprise the other components of thefiltration unit as described herein.

In another embodiment of this aspect, the filtration unit 100 adapted tocarry out the transition plenum method comprises an upper plate 105containing a plurality of perforations 113 a and an effluent pipe 117for the PRF 130, wherein the effluent pipe 117 is located below theupper plate 105. The filtration device for conducting the transitionplenum method may further comprise the other components of thefiltration unit as described herein.

The above configurations are exemplary in nature only and anyconfiguration of the filtration device described for use in thetransition plenum method may be used with the methods described herein.

Such method comprises providing a source of the SF, wherein the scouringfluid inlet pipe is in communication with the source for the SF anddirecting the SF through the described scouring fluid inlet pipes intothe filter bed. The method may further comprise providing a source ofPRF and directing the PRF into the filter bed as described herein. Themethod may still further comprise providing a blower for directing theSF and a pump for directing the PRF. In certain embodiments, thescouring fluid is compressed air. In certain embodiments, the particleremoval fluid is water. Any of the various flow rates for the SF and/orPRF as described for the transition plenum method may be used in suchmethod. For example, the flow rate of the PRF is less than 10 gpm/ft²,the flow rate of the SF is greater than 40 CFM/ft² and/or the ratio ofthe flow rate of the SF to the PRF is greater than 15 to 1.

In one aspect, the present disclosure provides for a method for carryingout a wash cycle in a filtration device comprising utilizing anapparatus for conducting the directed scouring fluid method transitionplenum method as described herein.

In one embodiment of this aspect, the filtration unit 100 adapted tocarry out the directed scouring fluid method and the transition plenummethod comprises a scouring fluid inlet pipe comprising a plurality ofopenings 151 on a top portion of the scouring fluid inlet pipe 119 and ascouring fluid nozzle 150 in fluid communication with at least one ofthe openings 151, an upper plate 105 containing a plurality ofperforations 113 a and an effluent pipe 117 for the PRF 130, wherein theeffluent pipe 117 is located above the upper plate 105 and the distanceY is less than 15 inches, wherein the scouring fluid nozzles comprise arestriction point to provide a jet force to the scouring fluid. Thefiltration device for conducting the directed scouring fluid method andthe transition plenum method may further comprise the other componentsof the filtration unit as described herein.

In another embodiment of this aspect, the filtration unit 100 adapted tocarry out the directed scouring fluid method and the transition plenummethod comprises a scouring fluid inlet pipe 119 comprising a pluralityof openings 151 on a top portion of the scouring fluid inlet pipe 119and a scouring fluid nozzle 150 in fluid communication with at least oneof the openings 151, an upper plate 105 containing a plurality ofperforations 113 a and an effluent pipe 117 for the PRF 130, wherein theeffluent pipe 117 is located below the upper plate 105, wherein thescouring fluid nozzles comprise a restriction point to provide a jetforce to the scouring fluid. The filtration device for conducting thedirected scouring fluid method and the transition plenum method mayfurther comprise the other components of the filtration unit asdescribed herein.

The above configurations are exemplary in nature only and anyconfiguration of the filtration device described for use in the directedscouring fluid method and the transition plenum method may be used incombination with one another with the methods described herein.

Such method comprises providing a source of the SF, wherein the scouringfluid inlet pipe is in communication with the source for the SF anddirecting the SF through the described scouring fluid inlet pipes intothe filter bed, wherein the SF has jet force generated by the scouringfluid nozzles. The method may further comprise providing a source of PRFand directing the PRF into the filter bed as described herein. Themethod may still further comprise providing a blower for directing theSF and a pump for directing the PRF. In certain embodiments, thescouring fluid is compressed air. In certain embodiments, the particleremoval fluid is water. Any of the various flow rates for the SF and/orPRF as described for the transition plenum method may be used in suchmethod. For example, the flow rate of the PRF is less than 10 gpm/ft²,the flow rate of the SF is greater than 40 CFM/ft² and/or the ratio ofthe flow rate of the SF to the PRF is greater than 15 to 1.

In certain embodiments of the above methods, the porous filtration mediais a synthetic porous filtration media or a compressible filtrationmedia.

In certain embodiments of the above methods, the porous filtration mediacontains trapped particulate contaminants and the wash cycle removes atleast 60% of the trapped contaminant particles. In certain embodiments,the duration of the wash cycle is less than or equal to 20 minutes.

In certain embodiments, the duration of the wash cycle is less than orequal to 15 minutes.

In certain embodiments, the duration of the wash cycle is less than orequal to 10 minutes.

In certain embodiments of the above methods, the porous filtration mediacontains trapped particulate contaminants and the wash cycle removes atleast 80% of the trapped contaminant particles. In certain embodiments,the duration of the wash cycle is less than or equal to 35 minutes.

In certain embodiments of the above methods when a scouring fluid nozzleis present, the restriction point may be located at any point in riser152. In one embodiment, the restriction point 153 is located at oradjacent to opening 152 a; in such an embodiment, the restriction pointmay also contact, at least partially, opening 151. In anotherembodiment, the restriction point is located at or adjacent to end 152b. In another embodiment, restriction point 153 is located at a positionin between ends 152 a and 152 b. The restriction point may also beplaced at the center-line of riser 152 or left or right of thecenterline of riser 152. Further, in the foregoing aspects, the ratio ofthe cross sectional area of restriction point 153 to opening 151 in thescouring fluid inlet pipe 119 is less than 1.0 but greater than 0, suchas less than or equal to 0.8, such as 0.7, 0.6, 0.5, 0.4 or 0.3. Inanother embodiment, the ratio of the diameter of restriction point 153to opening 151 is from 0.3 to 0.8.

In certain embodiments of the above methods when a scouring fluid nozzleis present, the scouring fluid nozzles 150 may be selected from theembodiments below (with reference numbers corresponding to FIGS. 3D-3F).

In one embodiment, the scouring fluid nozzle 150 comprises a riser 152having an open first end 152 a and an open second end 152 b joined byside walls 152 d and forming a passage 152 c and one or more flanges 152e (which provide the restriction point 153). As discussed herein, theplacement of the flange(s) 152 e may be placed at various locations inriser 152.

In another embodiment, the scouring fluid nozzle 150 comprises a riser152 having an open first end 152 a and an open second end 152 b joinedby side walls 152 d and forming a passage 152 c and a restrictor 154,the restrictor comprising a body 155 with an opening 156 through body155 (which serves as restriction point 153). In this aspect, the riser152 is in fluid communication with opening 151 through opening 156 ofrestrictor 154. As discussed herein, the placement of the restrictor 154may be placed at various locations in riser 152.

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c and a nozzle 157(which serves as restriction point 153).

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c, with at leastone of side walls 152 d having an inward deflection 160 (which serves asrestriction point 153).

The pinch point may be created as discussed herein, such as by a nozzle157 or inward deflection 160. As discussed herein, the nozzle 157 orinward deflection 160 may be placed at various locations in riser 152.

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c, wherein theriser 152 is provided with passage 152 c that has a diameter less thanthat of opening 151 (which serves as the restriction point 153). Theriser 152 is secured to the scouring fluid inlet pipe 119 as discussedherein, such as by legs 162.

In still another embodiment, the scouring fluid nozzle 150 comprises ariser 152 having an open first end 152 a and an open second end 152 bjoined by side walls 152 d and forming a passage 152 c and a restrictionpoint 153, wherein the diameter of passage 152 c continues to berestricted for at least a portion of the distance between restrictionpoint 153 to end 152 b.

Measurement of the Degree of Cleaning

The DOC is one endpoint for demonstrating the improved function of themethods and devices of the present disclosure. A variety of methods maybe used to measure the degree of cleaning. The following is an exemplarymethod for determining the DOC.

The first step in the testing process is pre-soiling the porousfiltration media to be tested in the wash cycle. The porous filtrationmedia is pre-soiled under controlled conditions. For example, afiltration unit is designated for all tests and the filtrationconditions are standardized for each test (equal amount and type ofdirty influent, same flow rate, equal weight of porous filtration media,equal flow pressure etc.). The dirty influent, which simulates thereal-world fluid to be filtered, may be prepared by dissolving a setamount of pre-engineered solid particles into a set amount of fluid (forexample water) to produce a standardized dirty influent. Thepre-engineered solids may have a defined particle size range to closelysimulate the particle size range in the fluids to be filtered undernormal operating conditions. Using the standardized dirty influent, thefiltration unit is run for a pre-determined amount of time (run-time).The run-time may be set to correspond to actual times between washcycles in normal operation, may be set to an arbitrarily determined time(for example 1 hour), or may be determined when a specific change inpressure is observed in the operation of the filtration unit (which is asurrogate for the amount of solids collected by the porous filtrationmedia); other means to set the run-time may also be used. Before thesoiling process is begun, a sample of media is extracted from the mediabed, dried and weighed to determine the “Before Soiling” Weight of theMedia (Before Soiling Weight). After the soiling process is completed, asample of media is extracted from the media bed, dried and weighed todetermine the “After Soiling” Weight of the Media (After SoilingWeight).

The test procedures now advance to the wash testing phase. The soiledmedia can be wash tested in the same physical unit used for the soilingstep or the soiled media can be transferred to a unit designedspecifically for wash testing; in either case, the unit is referred toas the “wash testing unit”. The wash testing unit may incorporate one orboth of the improvements described herein. When an entire batch ofsoiled media is not used in a single run, equal amounts of the soiledmedia are used for each wash test (for example, based on weight of themedia or based on the number of individual media units). The soiledmedia is subjected to a wash cycle under controlled conditions. Forexample, potable water may be used as the PRF and the PRF used at thesame pressure, flow rate and temperature in all wash tests. The washcycle time may be varied. For certain tests, the wash cycle time ismaintained as a constant between tests. In other embodiments, the washcycle time may be varied. The wash cycle time may be determined asdesired. For example, the wash cycle time may be: i) based on the lengthof the wash cycle under normal operating conditions (for example 30-35minutes); ii) set to a series of pre-determined times that are less thanthe length of a wash cycle under normal operating conditions (forexample 5 minutes, 10 minutes, 15 minutes, 20 minutes etc.); iii) set toa series of pre-determined abbreviated washing steps of purposefullyselected durations (for example: a first wash segment of 3 minutesduration, a second wash segment of 4 minutes duration, a third of 8minutes duration and a fourth of 10 minutes duration or a first washsegment of 10 minutes duration, a second wash segment of 8 minutesduration, a third of 8 minutes duration and a fourth of 8 minutesduration); iv) set to end based on a characteristic of the effluent; orv) set to end based on a parameter of the system (for example, change inpressure of the PRF). The wash cycle may use each of the improvementsdescribed herein separately and each of the improvements together.Furthermore, wash cycles may be conducted using the device of the priorart (without the improvements described herein). In addition, astringent wash cycle using chemical agents (for example detergents) in acommercial washer may also be used to determine the maximum amount ofthe pre-engineered particles that can be removed from the pre-soiledmedia for comparison purposes (referred to as the “maximum wash”).

After the completion of each wash testing step and/or after eachcompleted wash cycle, a sample of the media is removed, dried andweighed under controlled conditions. The sample may be the entire amountof media used in the wash testing step and/or wash cycle or a portionthereof. The weight of the dried media reflects the weight of theretained particles as well as the weight of the media (referred to asthe “washed weight”). As the original weight of the media that was usedin the test is known, this weight may be subtracted from the washedweight if desired. Alternatively, the weight of the media may be assumedto be equal across all wash tests given the controlled conditionsdescribed above and the determined washed weight may be used directly.

The washed weight may be compared between wash cycles using theimprovements, both alone and in combination, with the washed weightdetermined using the wash cycle of the prior art device described hereinand the maximum wash as described above. For example, the washed weightfor media subjected to a wash cycle using only the directed scouringimprovement may be directly compared to the washed weight for mediasubject to a wash cycle of the prior art device. As another example, thewashed weight for media subjected to a wash cycle using only thetransition plenum improvement may be directly compared to the washedweight for media subject to a maximum wash. The lower the washed weight,the higher the DOC.

In another approach, the weight of particulates removed (for example ingrams) is determined for each wash condition by subtracting the washedweight from the soiled weight. Therefore, the amount of particulatesremoved for each wash condition may be directly compared. For example,the weight of particulates removed from media subjected to a wash cycleusing only the directed scouring improvement may be directly compared tothe weight of particulates removed from media subject to a wash cycle ofthe prior art device. As another example, the weight of particulatesremoved from media subjected to a wash cycle using the transition plenumimprovement and the directed scouring fluid improvement may be directlycompared to the weight of particulates removed from media subject to themaximum wash. The greater the weight of particulates removed, the higherthe DOC.

Furthermore, the percentage of maximum clean can also be determined. Insuch an approach, the weight of particulates removed from media subjectto the maximum wash is determined as well as the weight of particulatesremoved from media subject to various washing conditions. For example,the weight of particulates removed from media subjected to a desiredwash condition is divided by the weight of particulates removed frommedia subject to the maximum wash and multiplied by 100 to determine apercentage of maximum clean. For example, the percentage of maximumclean for media subjected to a wash cycle using only the transitionplenum improvement may be directly compared to the percentage of maximumclean for media subject to a wash cycle of the prior art device. Asanother example, the percentage of maximum clean for media subjected toa wash cycle using the transition plenum improvement and the directedscouring improvement may be directly compared to the percentage ofmaximum clean for media subject to a wash cycle using only the directedscouring improvement. The higher the percentage of maximum clean, thehigher the DOC.

In another example, the rate of change of the DOC is measured. In thisapproach, pre-soiled media is subject to a wash cycle using the maximumwash as described above for short intervals of time that are less thanthe wash cycle time normally used (for example, for 8 minutes, 16minutes and 24 minutes) and the DOC determined for each time interval.The DOC can be measured by the percentage of maximum clean; however,other measures of DOC may be used, such as the weight of particulatesremoved or the washed weight if desired. The DOC for the wash can beplotted graphically with time on the x axis and, percentage of clean (orother measure of DOC) on the y axis. Similarly, pre-soiled media issubject to a wash cycle using the improvements described herein, eitheralone or in combination and/or using the wash cycle of the prior artdevice described herein. The same intervals of time are chosen as usedfor the maximum wash test. The results for each condition are plottedgraphically as described above and compared to the plot obtained for themaximum wash condition. From a comparison of the graphs, the time takento reach a certain DOC parameter (for example, percent of maximum clean)can be determined for each wash cycle condition and the resultscompared. For example, the time taken to reach 50% of the specified DOCparameter or 90% of the specified DOC parameter can determined for eachwash cycle condition and compared.

Example 1

Both the filtration device of the present disclosure and the prior artfiltration device were tested to determine the improvement in removal oftrapped solids from the compressible filtration media during the washcycle realized using the filtration device of the present disclosure.The testing methods involved generally two steps. The first step was a“filtration” step in which the compressible filtration media (asdescribed below) was exposed to a fluid stream containing particulatecontaminants such that the compressible filtration media removedparticulate contaminants from the fluid stream. As the filtration stepprogressed over time, the compressible filtration media captured moreand more particulate contaminants from the fluid stream. At the end ofthe filtration step, the compressible filtration media can be referredto as “soiled,” indicating that the compressible filtration media hasremoved a desired portion of the particulate contaminants from the fluidstream, thereby trapping the particulate contaminants within thecompressible filtration media. The second step comprised subjecting thesoiled compressible filtration media to a “washing” or “cleaning” step.The purpose of the washing step is to remove at least a portion of thetrapped particulate contaminants from the compressible filtration mediaso as to prepare the compressible filtration media for subsequent roundsof filtration. As discussed herein, filtration media (regardless oftype) is required to be cleaned periodically to maintain the ability toremove contaminants. The greater the degree of cleaning of thecompressible filtration media (i.e., the more of the entrappedparticulate contaminants are removed from the compressible filtrationmedia) during the washing step and the length of time required toachieve a certain or desired degree of cleaning are importantconsiderations in the washing step.

The compressible filtration media used to form the filter media bed inthis example was that described in U.S. Pat. No. 7,374,676. Eachcompressible filtration media unit was a fibrous sphere approximately1.25 inches in diameter manufactured from synthetic materials. Eachindividual compressible filtration media unit was manufactured from alarge number of synthetic fibers bound together in the center of theunit by a band. The compressible filtration media units are capable ofbeing compressed in order to adjust the porosity and the size of theparticulate contaminants that are trapped. Approximately 15,000individual compressible filtration media units were used to form thefilter media bed for tests described in this example.

To determine the degree of cleaning (DOC) accomplished by the filtrationdevices of the prior art (sometimes referred to as the “OldConfiguration” as illustrated in FIGS. 1, 2A & 2B) and the filtrationdevices of the present disclosure (sometimes referred to as the “NewConfiguration” as illustrated in FIGS. 3A to 3G and 4A to 4C), a testunit was developed that allowed the components required for the washingstep in the prior art filtration devices and the filtration devices ofthe present disclosure to be substituted for one another while keepingthe remaining components of the test unit the same.

The test unit is shown in FIG. 5. The test unit is a full scalecommercial size 3 foot by 3 foot cross-sectional area filtration deviceconstructed specifically to perform the testing as described in thisExample. The operation of the test unit 1000 is now described. The testunit was operated the same for tests using the Old Configuration and theNew Configuration, with the exception of the washing step as describedbelow. FIG. 5 shows the test unit 1000 with filter media bed 1001, PRFholding tank 1002, influent feed tank 1004 and pump 1006 to drive theinfluent and PRF. Line 1100 is in fluid communication with the influentfeed tank and the pump 1006. Line 1102 is in fluid communication withthe pump 1006 and the test unit 1000 and serves to direct the influentinto the test unit 1000. Line 1102 is also equipped with additive feedlines 1102 a, 1102 b, 1102 c to allow introduction of the additiveconstituent components necessary to produce an influent having thecharacteristics of influent encountered in real-world applications. Theflow rate of each of the additives is controlled during the filtrationstep to maintain the appropriate concentration of influent componentsthroughout the filtration step. The additives are not added during thewashing step and the additive feed lines are closed. Line 1104 is influid communication with the test unit 1000 and the influent feed tank1004 and serves to recycle the effluent from the test unit back to theinfluent feed tank and ultimately back to the test unit through lines1100 and 1102. Line 1104 is closed during the washing step. Line 1106 isin fluid communication with the PRF holding tank 1002 and the pump 1006while line 1008 is in fluid communication with pump 1006 and the testunit and serves to direct the PRF into the test unit during the washingstep. Line 1110 a and line 1110 b are each in fluid communication withthe test unit 1000 and serves to remove the PRF fluid and releasedparticulate contaminants from the test unit 1000 for collection ordisposal during the wash step (they are each particle removal fluideffluent pipes). Lines 1110 a and 1110 b are each closed during thefiltration steps. Line 1110 b was used for removal of the PRF for testsusing the New Configuration (and was therefore closed during the washingstep in tests using the Old Configuration). Line 1110 a was used forremoval of the PRF for tests using the Old Configuration (and wastherefore closed during the washing step in tests using the NewConfiguration). As discussed herein, the relative position of the upperplate to the particle removal fluid effluent pipe and the distance fromthe top surface of the lower plate to the bottom of the invert of theparticle removal fluid effluent pipe are each factors that can bemodulated to influence the creation of the transition plenum asdiscussed herein. Pump 1006 and the piping system are each equipped withswitching valves as is known in the art to allow the direction ofinfluent during the filtration step or PRF during the washing step asappropriate. The test unit is also equipped with various ancillarycomponents required for operation, such as, but not limited to, apressure sensing device to measure differential pressure across themedia filter bed as described below and peristaltic pumps to control theaddition of the additive constituent components necessary to produce theinfluent as described. The test unit 1000 further comprised a SFdelivery system 1200, which is capable of being switched to allow the SFto be delivered by the methods of the prior art (the Old Configuration)and to allow the SF to be delivered by the methods of the presentdisclosure (the New Configuration). A blower (not shown in FIG. 5) wasused to introduce the SF at the rate as described herein.

The test unit operated as described herein. Briefly, the test unitcontained a filter media bed comprising the compressible filtrationmedia units contained by the walls of the test unit, an upper and alower plate, with the upper plate being movable with respect to thelower plate to compress the filter media bed during the filtration stepand to allow the filter media bed to be expanded during the washingstep. Each plate contained perforations to allow the various fluids toflow through while still retaining the compressible filtration media inthe filter media bed. As discussed herein, in operation during thefiltration step the compressible filtration media is compressed todefine a porosity gradient in the filter media bed proceedingprogressively from more porous to less porous in the direction of theflow of the influent fluid so that filtration proceeds in a directionfrom a more porous to a less porous filter media bed. In such operation,the larger particles are initially retained or captured in the portionof the filter media bed where the compressible filtration media have thelargest pore size and smaller particles are retained or captured laterin the portion of the filter media bed where the compressible mediafilter has smaller pore size.

For each test of the devices of the prior art (the Old Configuration)and the devices of the present disclosure (the New Configuration), abatch of new filtration media was placed in the test unit to form thefilter media bed as described above. Two runs were performed using thedevices of the prior art and the devices of the present disclosure.During each test, samples of the compressible filtration media wereobtained from the filter media bed at the time points described below.Each sample was taken from approximately the same portion of the filtermedia bed through a sealable opening in the test unit using the samesampling device. From each sample taken, 20 individual compressiblefiltration media units were removed at random, labeled and processed asdescribed herein. Any remaining compressible filtration media units wereplaced back into the filter media bed.

After creation of the filter media bed, a sample of 20 individualcompressible filtration media units, identified as the “Before Soiling”Sample, was taken from the filter media bed prior to beginning thefiltration step. The test unit was then placed into a filtration cyclefor the purpose of “soiling” the compressible filtration media. Theinfluent to the test unit during the filtration cycle was a fluid stream(potable water) containing particulate contaminants that wasspecifically engineered to significantly and visually soil thefiltration media and to mimic the particulate contaminants seen inreal-world operations. This real-world simulated influent was preparedby adding carefully controlled amounts of each of the followingconstituent additives to the potable water flowing from the PRF holdingtanks to yield an influent having the concentrations of each of theseadditives as indicated by the values in brackets [ ]: anionic frictionreducer polymer DCF-223/CT-223 [0.5 ppm], pre-engineered solids (“PES”)(ISO 121103-1, A4 Coarse Test Dust, [100 mg/L]) and partially digestedbio-solids [25 mg/L] (extracted from a local wastewater treatmentfacility).

The influent entered the test unit 1000 through line 1102 and passedthrough the test unit at a flow rate of 135 gallons per minute, whichwas equivalent to 15 gallons per minute per square foot of the filtermedia bed cross-sectional area. During the filtration step, the effluentfrom the test unit 1000, which exits the test unit via line 1104, isreturned to the influent feed tank 1004 in a continuously recyclingmanner. As described above, the additive components of the influentmixture were injected into to the recycled influent stream prior toreintroduction into the test unit 1000 throughout the filtration step.

The filtration step was continued until the differential pressure acrossthe media filter media bed rose to the maximum operational limit. Whenthe pressure indicator at the bottom of the test unit read 7.8 psi, thefiltration step was stopped as the compressible filtration media wasconsidered fully-soiled and at this point the filtration step wasdetermined to be complete. A sample of 20 individual compressiblefiltration media units were taken and identified as the “After Soiling”Sample.

Immediately following the filtration step, the test unit was placed intothe wash step for cleaning of the compressible filtration media. For allof the tests of this example, pressurized air served as the SF andpotable water served as the PRF. The SF was delivered at 135 CFM and theflow rate of the PRF was set to 90 gallons per minute or 10 gallons perminute per square foot of the filter media bed cross-sectional area. TheSF was delivered to the test unit though the SF delivery unit 1200,which was different in the Old Configuration versus the NewConfiguration as described herein. The H_(W):H_(F) ratio for tests usingboth the Old Configuration and the New Configuration was 3:33:1, withthe height of the filter bed being 18 inches during the filtration stepand the height of the filter bed during the washing step being 60inches.

For the Old Configuration, the SF delivery system 1200 comprised twoscouring fluid inlet pipes as shown in FIG. 2A and FIG. 2B herein (withthe scouring fluid inlet pipe being designated 19 in such figures) whichreleased the SF through exit channels (designated 19 a in FIGS. 2A and2B) disposed on the bottom portion of the scouring fluid inlet pipe (theportion of the pipe farthest away from bottom plate 7 in FIGS. 2A and2B). As discussed herein, the SF is initially directed downwards awayfrom the expanded compressible media filter media bed, dissipating asubstantial portion of the motive force of the SF. The released SF risesand passes through perforations in lower plate of the filtration unit toagitate the expanded compressible media filter media bed. In theparticular embodiment of the Old Configuration tested, two scouringfluid inlet pipes were employed, with each scouring fluid inlet pipehaving 29 exit channels for release of the SF. Each scouring fluid inletpipe was designated as either an A side or B side and the SF wasintroduced through the A side scouring fluid inlet pipe for two minutesfollowed by introduction of the SF through the B side scouring fluidinlet pipe for two minutes. This alternating procedure was repeated fora total of34 minutes. In the configuration tested, each of the A and Bside scouring fluid inlet pipe was a branched scouring fluid inlet pipe.As shown in FIG. 5, Line 1110 a was used for removal of the PRF fortests using the Old Configuration. Line 1110 a is located farther awayfrom the top surface of the lower plate and farther away from the upperplate than line 1110 b (which was used for the same purpose in the testunit for testing the New Configuration). The corresponding values for Zand Y (as such values are described herein) for the filtration unitoperating in the Old Configuration were 83 inches and 22 inches,respectively (note that the value X does not exist in the OldConfiguration as discussed herein). Due to the above-describedconfiguration, no transition plenum was created in the tests when thetest unit was in the Old Configuration.

For the New Configuration, the SF delivery system 1200 similarlycomprised two scouring fluid inlet pipes (as shown in FIGS. 3A to 3C anddesignated 119) which released the SF through a plurality of scouringfluid nozzles (as shown in FIGS. 3A to 3C and designated 150). Thescouring fluid nozzle 150 comprised a riser portion having an open firstend and an open second end joined by side walls forming a passage, and arestriction point located with the riser. The second open end of eachscouring fluid nozzle was placed in close proximity to a perforation inbottom plate to direct the SF through the perforation and into thecompressible media filter media bed. As discussed herein, the SF isreleased with a jet force as it exits the scouring fluid nozzleimparting additional energy to the SF and allowing for more efficientcleaning of the compressible filtration media. In the particularembodiment of the New Configuration tested, two scouring fluid inletpipes were employed, with each scouring fluid inlet pipe having 15scouring fluid nozzles for release of the SF. Each scouring fluid inletpipe was designated as either an A side or B side and the SF wasintroduced through the A side scouring fluid inlet pipe for two minutesfollowed by introduction of the SF through the B side scouring fluidinlet pipe for two minutes. This alternating procedure was repeated fora total of 34 minutes. In the configuration tested, each of the A and Bside scouring fluid inlet pipe was a branched scouring fluid inlet pipe.

As shown in FIG. 5, Line 1110 b was used for removal of the PRF fortests using the New Configuration. Line 1110 b is located closer to thetop surface of the lower plate and closer to the bottom portion of theupper plate than line 1110 a (which was used for the same purpose in thetest unit for testing the Old Configuration). The corresponding valuesfor Z, Y and X (as such values are described herein) for the filtrationunit operating in the New Configuration are inches, 4 inches and 1 to 4inches, respectively (the value is provided as a range for X as theindividual compressible filtration media units constantly in motion dueto the influence of the SF and the PRF such that a constant surface isnot present). Due to the above-described configuration, a transitionplenum was also created in the tests when the test unit was in the NewConfiguration.

At defined time intervals, the SF and the PRF were both turned-off toallow the extraction of sample of the individual compressible filtrationmedia units (20 units). In the tests performed samples were obtained at10 min, 18 min, 26 min, and 34 min after the initiation of the washingstep.

At the end of the 34 minute washing step, the test was consideredcomplete. Each test run yielded six (6) samples, with each samplecomprising 20 units of the compressible filtration media. The sampleswere designated as shown below:

1). BS: Before Soiling 2). AS: After Soiling 3). 10 m: After 10 minutesof washing 4). 18 m: After 18 minutes of washing 5). 26 m: After 26minutes of washing 6). 34 m: After 34 minutes of washing

Each of the six samples for each test was processed as described belowand each sample was analyzed independently. Each sample comprising the20 individual compressible filtration media units was placed in a dryingpan and dried for 24 hours at 250 F. Following drying, each sample wasweighed on a digital balance having an accuracy of 1/10,000 of a gram.The weight of the drying pan, which was previously determined, wassubtracted from sample weight to determine the final weight of the mediaand the captured particles contained in the media (when present).Dividing the final as dried weight by 20 (i.e. the number of individualcompressible filtration media units in the sample) yielded the averageweight of the compressible filtration media units (which in samples 2 to6 also contained varying amounts of entrapped particulate contaminants).

The metric used in determining the DOC in this example was the physicalparameter of average weight of one individual compressible filtrationmedia unit taken from the filter media bed (expressed in grams). Usingstatistical analysis by sampling, it can be shown that a sample of 20individual compressible filtration media units extracted from a filtermedia bed composed of 15,000 individual compressible filtration mediaunits would be sufficient to provide the accuracy need for this DOCanalysis. Specifically, a sample of 20 individual compressiblefiltration media units removed from a filter media bed having a total of15,000 individual compressible filtration media units yielded aconfidence level of 90% with a margin of error of 16%. The averageweight of each individual compressible filtration media unit (in grams)in each sample is used in the calculations below.

The primary parameter for determining the effectiveness of the washingstep of the compressible filtration media in this example is the DOC.Conceptually, the DOC is simply a measure of the amount of thoseparticulate contaminants captured by the filtration media during thefiltration step that were removed during the washing step. The DOC wascalculated as follows to yield a “% Clean” value:% Clean=[(“Particulate Contaminants Removed” duringWashing)/(“Particulate Contaminants Deposited” during filtration)]×100%

For example, when all of the Particulate Contaminants Deposited areremoved from the filtration media during the washing step, thefiltration media was said to be 100% Clean and the DOC=100%. Conversely,if none of the Particulate Contaminants Deposited are removed during thewashing step, the filtration media was said to be 0% Clean and theDOC=0%.

The amount of Particulate Contaminants Deposited during any filtrationstep is determined by subtracting the weight of the filtration mediabefore being subject to the filtration step (sample 1) from the weightof the filtration media at the end of the filtration step (sample 2).Therefore, the Particulate Contaminants Deposited=Sample 2 (AS)—Sample 1(BS). For Example, using the values obtained for the NC #2 test, theParticulate Contaminants Deposited=3.1568−2.4068=0.75

The amount of the Particulate Contaminants Removed is calculated bysubtracting the amount of retained solids in the filtration media at aparticular time during the washing step (samples 3 to 5) or at the endof the washing step (sample 6) from the Particulate ContaminantsDeposited value (as determined above). The amount of retained solidsvalue is calculated by taking the weight of the filtration media at aparticular time during the washing step (samples to 5) or at the end ofthe washing step (sample 6) and subtracting the weight of the filtrationmedia at prior to the initiation of the filtration step (sample 1).Therefore, to determine the Particulate Contaminants Removed at 10minutes into a washing cycle, the Particulate ContaminantsRemoved=[Sample 2 (AS)—Sample 1 (BS)]−[Sample 3 (10 min)—Sample 1 (BS)].Again, using the values obtained for the NC #2 test, the ParticulateContaminants Removed=[3.1568-2.4068]-[2.6646-2.4068], which onsimplification equals 0.4922.

Substituting the above values into the equation above, the % Clean after10 minutes of the washing step in NC #2=[(0.4922/0.75)]×100, which isequal to 65.6%. Therefore, for the 10 minute time point in the NC #2test, the % clean was 65.6%.

The results of the test conducted are shown below. Two tests wereconducted on the Old Configuration (OC #1 And OC #2) and two tests wereconducted using the New Configuration (NC #1 And NC #2). Table 1 showsthe raw average media weight data for samples 1 to 6 for OC #1, OC #2,NC #1 and NC #2 and the percent clean figure determined at the definedtime intervals for OC #1, OC #2, NC #1 and NC #2.

Table 2 shows the comparison between the percent clean values obtainedfor the Old and New Configurations and summarizes the improvement of thepercent cleaning value for the New Configuration over the OldConfiguration. The percent clean data in Table 1 was averaged for theOld Configuration and New Configuration to provide the values shown inTable 2. As shown in Table 2, the average degree of cleaning obtainedwith the New Configuration (65.2%) in the first 10 min of washing was34.1% greater than the average degree of cleaning obtained with the OldConfiguration in the first 10 min of washing (31.1%). Surprisingly, theaverage degree of cleaning obtained with the New Configuration (65.2%)in the first 10 min of washing was 22.2% greater than the average degreeof cleaning obtained with the Old Configuration in the entire 34 min ofwashing (43.0%). After completion of the washing step (34 min), theaverage percent clean obtained for the New Configuration (81.7%) was a38.7% greater than the average percent clean obtained with the OldConfiguration (43.0%). In addition, the average degree of cleaningobtained with the New Configuration at each time point of the washingstep was 28.5 to 38.7% greater (average of 33.9% greater) than theaverage degree of cleaning obtained with the Old Configuration.

The data in Tables 1 and 2 clearly show that the New Configurationincorporating the improved SF delivery apparatus and transition plenummethod as described herein provides for a greater DOC of filtrationmedia. Therefore, the improved SF delivery apparatus and transitionplenum method as described herein removed a higher percentage of trappedcontaminant particles than the device and method of the prior art.Furthermore, using the improved SF delivery apparatus and transitionplenum method as described herein allows for a dramatically reduced washcycle time (10 min versus 34 min) while at the same time achievingsignificant improvements in the DOC of the filtration media. Using thedevice and method of the present disclosure, a wash cycle of just 10minutes resulted in a greater DOC than that obtained with a full 34minute wash cycle using the device and method of the prior art. Due tothe greater DOC observed using the method and device of the presentdisclosure, the interval of time between wash cycles may be extended andthe interval of time between cleaning the filtration media with chemicaladditives may be extended. Such results are surprising when viewed inlight of the methods of the prior art.

TABLE 1 Degree of Cleaning as % Clean* Test Test Test Run 1 Run 2 TestRun 1 Run 2 Media Sample, I.D. OC #1 OC #2 NC #1 NC #2 Filtration Step:Before Soiling, BS 2.3195 2.4850 2.3199 2.4068 (Sample 1) After Soiling,AS 3.2182 3.0681 2.7562 3.1568 (Sample 2) Washing Step: 10 min ofWashing, W10 2.8564 2.9398 2.4735 2.6646 (Sample 3) % Clean after 10 minof 40.3% 22.0% 64.8% 65.6% Washing 18 min of Washing, W18 2.9789 2.78382.4536 2.6843 (Sample 4) % Clean after 18 min of 26.6% 48.8% 69.4% 63.0%Washing 26 min of Washing, W26 2.8526 2.8288 2.4737 2.5163 (Sample 5) %Clean after 26 min of 40.7% 41.0% 64.7% 85.4% Washing 34 min of Washing,W34 2.7098 2.8967 2.3972 2.5483 (Sample 6) % Clean after 34 min of 56.6%29.4% 82.3% 81.1% Washing *Weight expressed in grams

TABLE 2 Average % Clean After “t” Minutes of Wash Washing for theDuration Incremental Old New Average “t” Minutes Step ConfigurationConfiguration Improvement of Wash Wash OC Test Runs NC Test Runs In %Cleaning Time Time Prior Art Improved Art At each Washing Step After 10min 10 min 31.1% 65.2% 34.1% After 18 min +8 min 37.7% 66.2% 28.5% After26 min +8 min 40.9% 75.1% 34.2% After 34 min +8 min 43.0% 81.7% 38.7%Avg Improvement in % Cleaning per Washing 33.9% Step for NC over OC =Improvement in Total Cleaning for 34 minutes full wash 38.7% duration =

What is claimed:
 1. A method for carrying out a wash cycle in afiltration device comprising a filter bed of porous compressiblefiltration media units disposed within a housing, an upper perforatedplate and a lower perforated plate at least one of which is movable, afirst influent pipe, a first effluent pipe and a scouring fluid inletpipe comprising a plurality of openings on a top portion of the scouringfluid inlet pipe and a plurality of scouring fluid nozzles in fluidcommunication with said plurality of openings on the scouring fluidinlet pipe, the method comprising the steps of: a. introducing aparticle removal fluid from the first influent pipe into said housinguntil said filter bed is submerged; b. expanding said filter bed bymoving one of said plates and establishing a transition zone beneathsaid upper plate; c. directing a scouring fluid from the scouring fluidnozzles into the particle removal fluid, wherein the scouring fluidnozzles comprise a restriction point to provide a jet force to thescouring fluid which propels individual compressible filtration unitsout of the particle removal fluid through said transition zone at leastimpacting said upper plate and releasing trapped contaminant particlesfrom said compressible filtration media units; and d. removing theparticle removal fluid along with released contaminant particles fromthe filtration device through the first effluent pipe, wherein the firsteffluent pipe is located below the upper plate or located above theupper plate such that the distance from a bottom portion of the upperplate to a bottom invert on the first effluent pipe is 15 inches orless.
 2. The method of claim 1, wherein the wash cycle removes at least60% of the trapped contaminant particles by weight.
 3. The method ofclaim 2, wherein the duration of the wash cycle is less than or equal to20 minutes.
 4. The method of claim 1, wherein the wash cycle removes atleast 80% of the trapped contaminant particles by weight.
 5. The methodof claim 4, wherein the duration of the wash cycle is less than or equalto 35 minutes.
 6. The method of claim 1, wherein the scouring fluid iscompressed air.
 7. The method of claim 1, wherein there are 4 to 24scouring fluid nozzles.
 8. The method of claim 1, wherein the firsteffluent pipe is located above the upper plate such that a distance froma bottom portion of the upper plate to a bottom invert on the firsteffluent pipe is 5 inches or less.
 9. The method of claim 1, wherein thefirst effluent pipe is located above the upper plate such that adistance from a top of the lower plate to a bottom invert on the firsteffluent pipe is from 48 to 72 inches.
 10. The method of claim 1,wherein the first effluent pipe is located above the upper plate suchthat a distance from a top of the lower plate to a bottom invert on thefirst effluent pipe is from 62 to 70 inches.
 11. The method of claim 1,wherein the first effluent pipe is located above the upper plate suchthat a distance from a bottom portion of the upper plate to a bottominvert on the first effluent pipe is 5 inches or less and a distancefrom a top of the lower plate to a bottom invert on the first effluentpipe is from 62 to 70 inches.
 12. The method of claim 1, wherein eachscouring fluid nozzle comprises a riser having an open first end and anopen second end joined by side walls and forming a passage for thescouring fluid, wherein the restriction point is located at a positionwithin the riser and the second open end is in fluid communication withat least one of the openings on the scouring fluid inlet pipe.
 13. Themethod of claim 12, wherein the restriction point is located at oradjacent to the first open end, at or adjacent to the second open end orat a point in between the first open end and the second open end. 14.The method of claim 1, wherein steps (a), (b), and (c) are performedsequentially.
 15. The method of claim 1, wherein step (a) and step (b)are performed before step (c).
 16. The method of claim 1, where step (b)is performed before step (c).
 17. The method of claim 1, wherein steps(a) and (b) are performed simultaneously.